MC289953 – Microsoft identified and corrected an issue with users’ ability to access OneDrive for Business through the Office.com navigation menu. This issue was caused by a recently deployed code change and while Microsoft resolved the underlying issue, action is required to mitigate the impact for affected users. Microsoft previously communicated this issue to you via OD289670 in the Service Health Dashboard.
What actions do you need to take:
To fix this problem, affected users need to access OneDrive for Business directly via your specific tenant host URL. Users only need to complete this action once to self-mitigate this issue, as doing so manually pushes the UPN changes to Azure Active Directory. Once complete, users will be able to access the service from Office.com as expected.
How this will affect your organization:
If you don’t take action, users who had their User Principal Name (UPN) updated between September 18, 2021, and October 2, 2021, will be unable to access OneDrive for Business through the Office.com navigation menu.