Question Deluged with demands to update credentials

[kgnimbus]

I use Outlook email within Microsoft Office 365 on Windows 10 Pro.
Whilst all was well for some months, suddenly email after email is from Microsoft itself, demanding to update credentials. I did all this, but to no avail, as they just keep coming on all 5 outlook.com addresses and some also ask that I check syncing for btinternet.com addressses.
When Outlook opens I am also asked to enter my security pin before Outlook will open.
I have updated credentials as per normal instructions and have checked all syncing and everything seems to be as it should be...however, the emails just keep coming every time I open Outlook365.
Any help would be appreciated, as this is driving me nuts.

 

[hang-the-9]

Is this a corporate Office account? Did you check with Microsoft support? What you are seeing happens with two factor authentication and changing IPs or systems.

 

[kgnimbus]

No, it's just a home system, but two factor authentication does make sense.

Thanks for the info.