Calendar Server: No invitation confirmation sent for some invitations accepted through Thunderbird/Lightning

[gohrner]

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Steps to reproduce

1. NextCloud 18.0.8 (actually, apparently all versions, we tried with NC 16.x+), calendar exported through CalDAV, Thunderbird 68.12.0 as mail client, Thunderbird Lightning to sync CalDAV calendar.
2. An MS Outlook/Exchange user from a different organisation sends an event invitation by mail.
3. The NextCloud user accepts the invitation with Thunderbird (into the NextCloud CalDAV calendar).

Expected behaviour

NextCloud should send an confirmation mail to the inviter that the invitation was accepted.

Actual behaviour

No confirmation mail is sent.

I assume this is a bug, but might be a configuration issue. I first tried to get feedback in the forum, to no avail: https://help.nextcloud.com/t/no-invitation-confirmation-sent-for-some-invitations-accepted-through-thunderbird-lightning/90840

Server configuration

Operating system: Debian 10

Web server: Apache 2.4

Database: MariaDB 10.3

PHP version: 7.3

Nextcloud version: 18.0.8 (actually, apparently all versions, we tried with NC 16.x+)

Updated from an older Nextcloud/ownCloud or fresh install: Updated, original installation was 15.x or 16.x

Where did you install Nextcloud from: Official tar from NextCloud

Signing status:

Signing status

No errors have been found.

List of activated apps:

App list

Enabled:
  - accessibility: 1.4.0
  - activity: 2.11.0
  - apporder: 0.10.0
  - calendar: 2.0.4
  - cloud_federation_api: 1.1.0
  - comments: 1.8.0
  - contacts: 3.3.0
  - dav: 1.14.0
  - deck: 1.0.5
  - external: 3.5.0
  - federatedfilesharing: 1.8.0
  - federation: 1.8.0
  - files: 1.13.1
  - files_external: 1.9.0
  - files_markdown: 2.3.0
  - files_pdfviewer: 1.7.0
  - files_rightclick: 0.15.2
  - files_sharing: 1.10.1
  - files_trashbin: 1.8.0
  - files_versions: 1.11.0
  - files_videoplayer: 1.7.0
  - firstrunwizard: 2.7.0
  - impersonate: 1.5.2
  - logreader: 2.3.0
  - lookup_server_connector: 1.6.0
  - nextcloud_announcements: 1.7.0
  - notes: 3.6.4
  - notifications: 2.6.0
  - oauth2: 1.6.0
  - password_policy: 1.8.0
  - photos: 1.0.0
  - polls: 1.4.3
  - privacy: 1.2.0
  - provisioning_api: 1.8.0
  - recommendations: 0.6.0
  - richdocuments: 3.7.3
  - serverinfo: 1.8.0
  - settings: 1.0.0
  - sharebymail: 1.8.0
  - socialsharing_email: 2.1.0
  - spreed: 8.0.10
  - support: 1.1.1
  - survey_client: 1.6.0
  - systemtags: 1.8.0
  - tasks: 0.13.3
  - text: 2.0.0
  - theming: 1.9.0
  - twofactor_backupcodes: 1.7.0
  - updatenotification: 1.8.0
  - user_ldap: 1.8.0
  - viewer: 1.2.0
  - workflowengine: 2.0.0
Disabled:
  - admin_audit
  - encryption
  - files_readmemd
  - mail

Nextcloud configuration:

Config report

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "nextcloud.example.com"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "overwrite.cli.url": "https:\/\/nextcloud.example.com",
        "htaccess.RewriteBase": "\/",
        "dbtype": "mysql",
        "version": "18.0.8.2",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "\\OCA\\User_LDAP\\LDAPProviderFactory",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "sendmail",
        "mail_smtpauthtype": "LOGIN",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "theme": "",
        "loglevel": 0,
        "auth.bruteforce.protection.enabled": true,
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "updater.release.channel": "stable",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "enable_previews": true,
        "updater.secret": "***REMOVED SENSITIVE VALUE***"
    }
}

Are you using external storage, if yes which one: none

Are you using encryption: no

Are you using an external user-backend, if yes which one: LDAP

LDAP configuration (delete this part if not used)

LDAP config

+-------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Configuration                 |                                                                                                                                                                                                                                                     |
+-------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| hasMemberOfFilterSupport      | 1                                                                                                                                                                                                                                                   |
| homeFolderNamingRule          |                                                                                                                                                                                                                                                     |
| lastJpegPhotoLookup           | 0                                                                                                                                                                                                                                                   |
| ldapAgentName                 | cn=nextcloud,ou=system,dc=example,dc=com                                                                                                                                                                                                          |
| ldapAgentPassword             | ***                                                                                                                                                                                                                                                 |
| ldapAttributesForGroupSearch  |                                                                                                                                                                                                                                                     |
| ldapAttributesForUserSearch   |                                                                                                                                                                                                                                                     |
| ldapBackupHost                |                                                                                                                                                                                                                                                     |
| ldapBackupPort                |                                                                                                                                                                                                                                                     |
| ldapBase                      | dc=example,dc=com                                                                                                                                                                                                                                 |
| ldapBaseGroups                | dc=example,dc=com                                                                                                                                                                                                                                 |
| ldapBaseUsers                 | dc=example,dc=com                                                                                                                                                                                                                                 |
| ldapCacheTTL                  | 600                                                                                                                                                                                                                                                 |
| ldapConfigurationActive       | 1                                                                                                                                                                                                                                                   |
| ldapDefaultPPolicyDN          |                                                                                                                                                                                                                                                     |
| ldapDynamicGroupMemberURL     |                                                                                                                                                                                                                                                     |
| ldapEmailAttribute            | mail                                                                                                                                                                                                                                                |
| ldapExperiencedAdmin          | 0                                                                                                                                                                                                                                                   |
| ldapExpertUUIDGroupAttr       |                                                                                                                                                                                                                                                     |
| ldapExpertUUIDUserAttr        |                                                                                                                                                                                                                                                     |
| ldapExpertUsernameAttr        | uid                                                                                                                                                                                                                                                 |
| ldapExtStorageHomeAttribute   |                                                                                                                                                                                                                                                     |
| ldapGidNumber                 | gidNumber                                                                                                                                                                                                                                           |
| ldapGroupDisplayName          | cn                                                                                                                                                                                                                                                  |
| ldapGroupFilter               | (&(|(objectclass=groupOfNames)))                                                                                                                                                                                                                    |
| ldapGroupFilterGroups         |                                                                                                                                                                                                                                                     |
| ldapGroupFilterMode           | 0                                                                                                                                                                                                                                                   |
| ldapGroupFilterObjectclass    | groupOfNames                                                                                                                                                                                                                                        |
| ldapGroupMemberAssocAttr      | member                                                                                                                                                                                                                                              |
| ldapHost                      | ldaps://localhost/                                                                                                                                                                                                                                  |
| ldapIgnoreNamingRules         |                                                                                                                                                                                                                                                     |
| ldapLoginFilter               | (&(&(|(objectclass=inetOrgPerson))(|(memberof=cn=example-mitarbeiter,ou=gruppen,ou=example,dc=example,dc=com)(memberof=cn=example-entwickler,ou=gruppen,ou=example,dc=example,dc=com)))(|(uid=%uid)(|(mailPrimaryAddress=%uid)(mail=%uid)))) |
| ldapLoginFilterAttributes     |                                                                                                                                                                                                                                                     |
| ldapLoginFilterEmail          | 1                                                                                                                                                                                                                                                   |
| ldapLoginFilterMode           | 0                                                                                                                                                                                                                                                   |
| ldapLoginFilterUsername       | 1                                                                                                                                                                                                                                                   |
| ldapMatchingRuleInChainState  | unavailable                                                                                                                                                                                                                                         |
| ldapNestedGroups              | 1                                                                                                                                                                                                                                                   |
| ldapOverrideMainServer        |                                                                                                                                                                                                                                                     |
| ldapPagingSize                | 500                                                                                                                                                                                                                                                 |
| ldapPort                      | 636                                                                                                                                                                                                                                                 |
| ldapQuotaAttribute            |                                                                                                                                                                                                                                                     |
| ldapQuotaDefault              |                                                                                                                                                                                                                                                     |
| ldapTLS                       | 0                                                                                                                                                                                                                                                   |
| ldapUserAvatarRule            | default                                                                                                                                                                                                                                             |
| ldapUserDisplayName           | cn                                                                                                                                                                                                                                                  |
| ldapUserDisplayName2          |                                                                                                                                                                                                                                                     |
| ldapUserFilter                | (&(|(objectclass=inetOrgPerson))(|(memberof=cn=example-mitarbeiter,ou=gruppen,ou=example,dc=example,dc=com)(memberof=cn=example-entwickler,ou=gruppen,ou=example,dc=ohrner-it,dc=com)))                                                        |
| ldapUserFilterGroups          | example-mitarbeiter;example-entwickler                                                                                                                                                                                                               |
| ldapUserFilterMode            | 0                                                                                                                                                                                                                                                   |
| ldapUserFilterObjectclass     | inetOrgPerson                                                                                                                                                                                                                                       |
| ldapUuidGroupAttribute        | auto                                                                                                                                                                                                                                                |
| ldapUuidUserAttribute         | auto                                                                                                                                                                                                                                                |
| turnOffCertCheck              | 0                                                                                                                                                                                                                                                   |
| turnOnPasswordChange          | 0                                                                                                                                                                                                                                                   |
| useMemberOfToDetectMembership | 1                                                                                                                                                                                                                                                   |
+-------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

[bastien-effetb]

Hi,
I have the exact same issue, I am on centos 7, with php 7.3 and nextcloud 20.0.6.
This bug is happening on thunderbird 78.6.1 on windows, but also on evolution on fedora.

After a lot of testing I found a workaroud, when I receive an invitation, i first decline the invitation, then the event is added to my calendar, and if I then accept the invitation, the notification is sent to the inviter.
Not very easy but at least i can send a notification.

If I can help you to solve this problem please tell me.

Best regards

[bastien-effetb]

I understand now that all is working well when I disable the sharing of my calendar as explained in nextcloud/calendar#2055

[DTsdem]

Same issue here.
We have an fresh installed and configured Nextcloud-Server 21.0.1 and using Thunderbird 78.8.1 (64-Bit). For synchronization as recommended TBSync. We tested all constellations with shared calendars and private calendars. The result is allways the same: no confirmation is sent, when u first accept the invitation. The warkoaround above works fine, but i think there is no realtion to the issue with shared calendars.

There must be an solution. Sending confirmation is an essential part of a calendar software.

[szaimen]

Is this Issue still valid in NC21.0.3? If not, please close this issue. Thanks! :)

[bastien-effetb]

For me it is not working at all with 21.0.3...
Before on 20.0.6 it worked at least with the workaroud explained previously...

[trevor87]

On Nextcloud 20.0.9.1 it only works with the workaround mentioned above.

[cr1xu5]

My calendar was shared with a group, but without edit rights. No invitation confirmations were sent by accepting in Thunderbird.

When I remove the share to the group, confirmations are still not sent. I do however have a Shared link active.

Nextcloud 20.0.11
Calendar 2.3.0

Also found this report:
https://help.nextcloud.com/t/can-not-confirm-meeting-invitations/95037

[trevor87]

Currently I use the workaround described here: https://help.nextcloud.com/t/error-when-accepting-a-calendar-invite-on-thunderbird/65117/2:

Go to your calendar on Thunderbird
Right-click on your calendar name (on the left of the window)
Choose Properties
Check the box Prefer client-side email scheduling
Click OK

[s-gbz]

Currently I use the workaround described here: https://help.nextcloud.com/t/error-when-accepting-a-calendar-invite-on-thunderbird/65117/2:

Go to your calendar on Thunderbird
Right-click on your calendar name (on the left of the window)
Choose Properties
Check the box Prefer client-side email scheduling
Click OK

This seems to resolve the issue & is also my preferred way of sending invitations since I have "physical" proof that they've actually been send.

Also, not sure if someone mentioned this, but while some people (& their respective email clients/ servers) received invitations others have not. Flakiness is the real issue here.

Anyways, thanks for the help guys!

[pboguslawski]

Problem still exists in server v24.0.3 and calendar v3.4.2.

Just tested that when e-mail handling for remote CalDAV calendar is disabled in Thunderbird 91.11.0 (TB) and enabled in NextCloud (NC):

• when accepting external invitation in TB with saving event to NC calendar, no e-mail message with event acceptance is sent to exteral event organizer,
• then changing event acceptance status (i.e. to decline>accept>decline>...) in NC does not generate e-mail messages to exteral organizer neither,
• then changing event acceptance status (i.e. to decline>accept>decline>...) in TB generates e-mail message to external organizer from NC but sender name in such messages is incomplete, without user full name i.e. "via SystemName" not "John Test via SystemName",
• then changing event acceptance status (i.e. to decline>accept>decline>...) in NC does generate e-mail messages to external organizer with correct sender name i.e. "John Test via SystemName" (so it seems that until TB first changes acceptance status on existing event in NC, no e-mail messages are sent from NC).

Similar problem described in #19197

More, NC allows one to change such event details i.e. change event time, attendees and TB block it; but this was reported separately in nextcloud/calendar#4379

[szaimen]

Hi, please update to 24.0.9 or better 25.0.3 and report back if it fixes the issue. Thank you!

My goal is to add a label like e.g. 25-feedback to this ticket of an up-to-date major Nextcloud version where the bug could be reproduced. However this is not going to work without your help. So thanks for all your effort!

If you don't manage to reproduce the issue in time and the issue gets closed but you can reproduce the issue afterwards, feel free to create a new bug report with up-to-date information by following this link: https://github.com/nextcloud/server/issues/new?assignees=&labels=bug%2C0.+Needs+triage&template=BUG_REPORT.yml&title=%5BBug%5D%3A+

[gohrner]

@szaimen: I switched back from client side ITIP to server side notifications to test.

I can confirm, the problem still seems to persist with Nextcloud 25.0.3.

[ghost]

The Problem still exists with Nextcloud 27.1.10 and Mail 3.7.0.
Furthermore this problem isn't only appearing with thunderbird there are also not confirmations send if you accept the invitation directly in the mail app from within nextcloud.

[SebastianKrupinski]

Fixed: #44893