Hi all, I’ve seen a few reports about this now and I am so sorry for the trouble 
I know @RicardoE105 has done a lot of work on the OAuth2 side of things, perhaps he has an idea what might be causing the problem or what to look out for if n8n throws an “Unknown error” following the callback?
Perhaps you can also describe step by step how you have registered your Azure app so I can try and reproduce this on my side? I’ve tried registering a new Azure app just the other day on 0.204.0 and wasn’t able to reproduce this particular problem.
With 0.205.0 having trouble with remembering OAuth2 scopes, perhaps you can also check if the issue occurs with [email protected] for you @NickFR?