We suddenly started seeing failed logins for our Azure AD enterprise connection. When inspecting the log entry, you can see that the error description states the following:
The provided client secret keys for app '******************' are expired. Visit the Azure portal to create new keys for your app: https://aka.ms/NewClientSecret, or consider using certificate credentials for added security: https://aka.ms/certCreds.
This error indicates that the failure occurs on the Azure side and that the client secret keys generated within the Azure portal have expired.
The Microsoft developer forum has a post that outlines some steps you can take to renew the client secret keys and update your application: