Why does Outlook keep showing Access Denied or throwing errors?
Outlook desktop occasionally stops receiving new mail and displays an "Access Denied" badge or error messages, while Outlook on the Web throws network errors. These intermittent sign-in loops and authentication failures require users to repeatedly clear Credential Manager or wait for access to restore.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Checking service health dashboard
- 2Running Get-MailboxStatistics to check if affected users are mid-move
- 3Using desktop Outlook since its local cache keeps it quiet
- 4Clear SSO in Credential Manager
- 5Reset, delete, and redownload Outlook
- 6Rebuild the OST, repair or reinstall Outlook, or apply registry tweaks
- 7Force Outlook classic
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“We have a few users who are reporting not getting new mail in Outlook desktop, and OWA gives errors when trying to access mail items/calendar/etc across different endpoints.”source ↗
“Randomly, I will have users start reporting Outlook showing a badge and says "Access Denied" instead of their emails.”source ↗
“Sometimes they can just sign back in, other times it loops and lets them in after some time.”source ↗
“We have cleared the SSO in Credential Manager, and it lets us back in, but maybe it's a fluke. The issue comes back another day.”source ↗
“Today I had 3 different users in different tenants report the issue happening at the same time.”source ↗
“Just received an email from a user that has a bar across her new outlook "This message can't be saved right now. Please try again later."”source ↗
Where this came up
People with this problem also raised
- 7Why am I getting DMARC and SPF errors when emails deliver fine?
- 2Locked out of cloud service partner center after deauthorization
- 11Sync agent stops with Error 5 Access Denied after internet outage
- 5Locked out of new network switches because the consultant left
- 3How to fix sync problems on large Outlook mailboxes
- 7Why didn't our backup internet fail over?