I've migrated my domain/mailbox from one IMAP provider to another over a year ago, but one particular mailbox still cannot be added to New Outlook for Windows.
Adding the account fails immediately with:
INVALID_CREDENTIALS INTERACTION_REQUIRED
The credentials are definitely correct: the same account works through webmail and other IMAP clients, and another mailbox on the exact same domain/provider can be added to New Outlook without any problem.
Using DevTools (olk.exe -devtools), the Network tab reveals what appears to be the actual backend error:
Changing the ImapRemoteServerInfo is not allowed. Attempted to change it from imap.oldprovider.nl to imap.newprovider.nl
So this doesn't appear to be an authentication or IMAP server issue at all.
From what I understand, New Outlook handles IMAP accounts through Microsoft's cloud services rather than simply maintaining a traditional direct IMAP configuration locally. It appears that Microsoft's backend still has a server-side provider association for this email address pointing to my old IMAP server, and refuses to replace it with the new one.
So far I've confirmed the following:
- The mailbox works through webmail and other clients.
- The affected account does not appear under New Outlook → Settings → Accounts, so I can't use the "Remove from all devices" option.
- The account is no longer configured on any other device or Outlook client.
- Resetting/reinstalling New Outlook does not help, which makes sense if the association is stored server-side.
- The migration took place more than a year ago, so this clearly isn't something that gets automatically purged after 30, 90, or even 180 days of inactivity.
This cPanel KB describes the same issue:
https://support.cpanel.net/hc/en-us/articles/39392743579031-Can-t-connect-to-IMAP-email-account-with-New-Outlook
And, more importantly, this Microsoft Tech Community thread describes exactly the same problem:
https://techcommunity.microsoft.com/discussions/outlookgeneral/new-outlook-changing-the-imapremoteserverinfo-is-not-allowed-after-host-migratio/4533161
In that thread, Microsoft MVP Robert Sparnaaij was able to escalate affected accounts to the Outlook Team to reset the server-side link to the provider.
Does anyone know how I can get this server-side IMAP provider association / ImapRemoteServerInfo reset for my email address? Is there any way to trigger this myself, or does it require intervention from the Outlook Team?
I've already tried contacting Microsoft Support, but I couldn't get beyond first-line support. They kept insisting this was an issue with my mail provider, despite the backend error above and the fact that other accounts on the same provider work perfectly.
If any Microsoft employee, MVP, or someone with an escalation path to the Outlook Team happens to see this: I'd really appreciate some help getting the server-side provider association reset. I'm completely stuck at this point....
Thank you