Microsoft 365 Alert : Service Degradation – Exchange Online – Some users may be unable to access their Exchange Online mailboxes via Outlook on the web – RESOLVED
30/09/2022 08:16:00 AM (BST)
Issue Reported : 22/08/2022 09:03:00 AM UTC
Microsoft Reference : EX439381
Issue Status : RESOLVED
Issue Description : Users may have been unable to access their Exchange Online mailboxes via Outlook on the web.
More info : The impact was specific to some users who had archive and primary mailboxes located on the same subset of database infrastructure. Admins could run Get-Mailbox or Get-MailboxLocation to find out if archive and primary mailboxes were located on the same database infrastructure.
Scope of impact : Some users whose archive and primary mailboxes were located on the same subset of database infrastructure may have been impacted.
Final Update : 30/09/2022 08:16:00 AM – Microsoft has finished reaching out to previously affected users and have confirmed impact has been remediated.
Root cause : A user directory feature update introduced a code issue that was preventing some users with an archive and primary mailbox on the same database infrastructure from accessing their mailboxes via Outlook on the web.
Next steps : Microsoft is investigating how the code issue was introduced in the recent feature update so we can prevent similar impact in the future.