diff --git a/src/components/AppointmentConfigModal.vue b/src/components/AppointmentConfigModal.vue
index c57eb73df..817027f7f 100644
--- a/src/components/AppointmentConfigModal.vue
+++ b/src/components/AppointmentConfigModal.vue
@@ -195,7 +195,10 @@ export default {
 		...mapState(useSettingsStore, {
 			isTalkEnabled: 'talkEnabled',
 		}),
-		...mapState(useCalendarsStore, ['ownSortedCalendars']),
+		...mapState(useCalendarsStore, [
+			'ownSortedCalendars',
+			'allSortedCalendars',
+		]),
 		...mapStores(useAppointmentConfigsStore, useCalendarsStore, useSettingsStore),
 		formTitle() {
 			if (this.isNew) {
@@ -222,12 +225,12 @@ export default {
 		},
 		selectableConflictCalendars() {
 			// The target calendar is always a conflict calendar, remove it from additional conflict calendars
-			return this.ownSortedCalendars.filter(calendar => calendar.url !== this.calendar.url)
+			return this.allSortedCalendars.filter(calendar => calendar.url !== this.calendar.url)
 		},
 		conflictCalendars() {
 			const freebusyUris = this.editing.calendarFreeBusyUris ?? []
 			return freebusyUris.map(uri => {
-				return this.ownSortedCalendars.find(cal => this.calendarUrlToUri(cal.url) === uri)
+				return this.allSortedCalendars.find(cal => this.calendarUrlToUri(cal.url) === uri)
 			})
 		},
 		defaultConfig() {
diff --git a/src/store/calendars.js b/src/store/calendars.js
index b8b860081..8f02b9dc4 100644
--- a/src/store/calendars.js
+++ b/src/store/calendars.js
@@ -64,7 +64,7 @@ export default defineStore('calendars', {
 		},
 
 		/**
-		 * List of sorted calendars
+		 * List of sorted writable calendars
 		 *
 		 * @param {object} state the store data
 		 * @return {Array}
@@ -77,7 +77,7 @@ export default defineStore('calendars', {
 		},
 
 		/**
-		 * List of sorted calendars owned by the principal
+		 * List of sorted writable calendars owned by the principal
 		 *
 		 * @param {object} state the store data
 		 * @return {Array}
@@ -90,6 +90,18 @@ export default defineStore('calendars', {
 				.sort((a, b) => a.order - b.order)
 		},
 
+		/**
+		 * List all sorted calendars, including readonly
+		 *
+		 * @param {object} state the store data
+		 * @return {Array}
+		 */
+		allSortedCalendars(state) {
+			return state.calendars
+				.filter(calendar => calendar.supportsEvents)
+				.sort((a, b) => a.order - b.order)
+		},
+
 		hasTrashBin(state) {
 			return state.trashBin !== undefined && state.trashBin.retentionDuration !== 0
 		},