If an app in Azure AD requires user assignment and the user trying to login to the app is not assigned a role in the app, the user gets the generic AADSTS50105 error (The signed in user xxxxx is not assigned a role for the application xxxxx).

Now, what if user self-service assignment has been allowed - would it be possible to include a link to the error page linking directly to the access panel where the user could request access to the application? Something like "Request access" - then the user could just click that and requrest assignment.