A Microsoft file hosting and synchronization service.
Dear Customer,
Welcome to Microsoft Community.
Could you please help confirm whether the screenshot below is the error you facing?
After checking the error message, could you please confirm if you set up Conditional Access policy or not?
I noticed some users are facing the same issue because of Conditional Access policy.
Thanks for your time and patience.
Best regards,
Trang - MSFT | Microsoft Community Support Specialist