Outlook 2016 MFA freezes connecting to EXO

Hey guys,

unfortunately no replies yet. Btw I have created a Microsoft ticket, but they say "hey, we cannot guarantee 100% perfect Outlook connection." The support wanted to play through the default troubleshooting with cached mode on/off, new profile. I have been asked a lot if the modern authentication has been fully enabled and yes, as you can see in the screenshot it is a password prompt for the modern authentication.

So I'm still trying to force the Microsoft support to dig even deeper with a more technical approach.

In Azure Sign-Ins I have searched for the affected users had this Outlook problem today. Just before the helpdesk solved the problem, you can see a lot of errors for the non-interactive
sign-ins, you can see a lot of errors for the Office 365 Exchange Online resource via the Microsoft Office application.

The error coder AADSTS50078 is not included in the https://docs.microsoft.com/en-us/azure/active-directory/develop/reference-aadsts-error-codes#aadsts-error-codes.

Presented multi-factor authentication has expired due to policies configured by your administrator, you must refresh your multi-factor authentication to access '{resource}'.

So it looks like that users who got these errors in a row have the Outlook sign-in issue. But in total I see several thousands of these notifications in the tenant, in most cases single ones.

Are these Azure sign-in failures quite normal?
Should I cross-post this in the identity forum?

Kind regards,
woelki