If users encounter login issues and your authentication method is Azure, then this help article is a good place to start and review common login errors.
Error code 14
Error: Cannot authenticate user from access token [Error code 14]
Reason: This error is shown when the call to get user information fails. Glean expects the following fields to be returned in the user information response: email and name. One of the two fields is likely empty.
Resolution: Navigate to the Azure Admin portal. View the users properties and ensure email and name fields have a value.
User re-directed to login screen.
Error: User re-directed to login screen.
Reason: This is likely happening because the user's email in Azure has a domain that has not been added to Glean's allowed list.
Resolution: Reach out to Glean Support and ask that the user's domain be added to the list of allowed domains for your instance.
Error Code 13
Error: SSO code exchange failed [Error Code 13]
Reason: The client secret for your Azure App is expired.
Resolution: Navigate to your Azure App and generate a new client secret. In the Glean Admin Workspace Settings > Setup > Authentication, select your Azure App. Add the new Client Secret and Save the App.