Some users may be unable to access their Exchange Online mailboxes via Outlook on the web

Microsoft issued an incident report on 27 Sept 2022 (Tue) about issues in accessing Exchange Online mailboxes via Outlook on the web.

Users Affected Microsoft users
Start Time 27 Sept 2022 (Tue) 6:07 PM
End Time To be updated
User Impact Any user whose archive and primary mailboxes are located on the same subset of database infrastructure may be impacted.
 More info A user directory feature update introduced a code issue that prevents some users with an archive and primary mailbox on the same database infrastructure from accessing their mailboxes via Outlook on the web.
Status Microsoft has initiated the process of disabling the specific code set including the offending update to remediate the impact. Microsoft expects to have a more accurate estimation for impact resolution by their next update.

Last update by Microsoft: 28 Sept 2022 (Wed) 4:07 AM