Cryptic exceptions when attempting IWA / UP / Device Flow with an app that isn't registered as a public client

[bgavrilMS]

Which Version of MSAL are you using ?
Note that to get help, you need to run the latest version. Preview version are also ok.
For ADAL, please log issues to https://github.com/AzureAD/azure-activedirectory-library-for-dotnet
MSAL 4.1

What authentication flow has the issue?

• Desktop / Mobile
  • Interactive
  • Integrated Windows Auth
  • Username Password
  • Device code flow (browserless)

Repro
In the portal, users have the option of configuring the "default client type"

Note: This is quite confusing as I can configure redirect URIs for the public client but still have this checkbox set to "NO".

If I attempt IWA or Device Code Flow, the exception that we get back is:

MsalServiceException: AADSTS7000218: The request body must contain the following parameter: 'client_assertion' or 'client_secret'.

For U/P, the exception is:

.MsalClientException: Federated service at https://msft.sts.microsoft.com/adfs/services/trust/2005/usernamemixed returned error: ID3242: The security token could not be authenticated or authorized.

Proposed solution
Re-Throw meaningful exceptions.

[bgavrilMS]

Related bug reported by customer: Azure-Samples/active-directory-dotnetcore-devicecodeflow-v2#9