New Outlook cannot add migrated IMAP account after hosting migration – INVALIDCREDENTIALS INTERACTIONREQUIRED

New Outlook for Windows – IMAP account cannot be added after migration to a new hosting provider

I have an IMAP mailbox on a custom domain that was recently migrated from one hosting provider to OVH.

The email address has not changed. Only the hosting provider and IMAP/SMTP server have changed.

Current OVH settings:

IMAP: imap.mail.ovh.net

Port: 993

SSL/TLS

Username: full email address

SMTP: smtp.mail.ovh.net

Port: 465

SSL/TLS

Authentication: username/password

The credentials and current server settings are definitely correct:

Webmail works.

The same mailbox works in Classic Outlook on the same PC.

The same mailbox works with other mail clients.

The problem occurs only in New Outlook for Windows.

When adding the account in New Outlook, I enter the correct OVH password. After clicking Next, New Outlook fails with:

INVALIDCREDENTIALS INTERACTIONREQUIRED

Previously, I also received:

UNKNOWN undefined

Current Session ID:

cb411338-c7af-af4S-8cOf-8cbS6d94a611

I have already tried:

removing and re-adding the account,

restarting New Outlook,

resetting New Outlook,

reinstalling New Outlook,

verifying the OVH IMAP/SMTP settings,

verifying the credentials in Classic Outlook.

None of these changed the result.

This looks very similar to the Microsoft Q&A cases from 2026 concerning migrated IMAP accounts where the email address remains the same but the IMAP server changes.

In particular, this case appears highly relevant:

“New Outlook for Windows won't add a migrated IMAP account — Cloud Mailbox stuck on old server (ImapRemoteServerInfo locked), needs service-level reset.”

Another August 2026 case reports the explicit backend error:

Changing the ImapRemoteServerInfo is not allowed

when the IMAP server was changed after a hosting migration.

Could someone familiar with the New Outlook backend please confirm whether the Microsoft Cloud account associated with my email address may still contain the old IMAP server information?

If so, is there a supported way to reset/re-provision the IMAP Cloud Mailbox so that New Outlook can register the current OVH server?

Microsoft Support has already reviewed the case and confirmed that the issue appears to require deeper investigation, but their current support channel does not have access to modify or reset the IMAP backend association.

I specifically want to use New Outlook. Classic Outlook works, but it does not resolve the New Outlook issue. New Outlook for Windows – IMAP account cannot be added after migration to a new hosting provider

I have an IMAP mailbox on a custom domain that was recently migrated from one hosting provider to OVH.

The email address has not changed. Only the hosting provider and IMAP/SMTP server have changed.

Current OVH settings:

IMAP: imap.mail.ovh.net

Port: 993

SSL/TLS

Username: full email address

SMTP: smtp.mail.ovh.net

Port: 465

SSL/TLS

Authentication: username/password

The credentials and current server settings are definitely correct:

Webmail works.

The same mailbox works in Classic Outlook on the same PC.

The same mailbox works with other mail clients.

The problem occurs only in New Outlook for Windows.

When adding the account in New Outlook, I enter the correct OVH password. After clicking Next, New Outlook fails with:

INVALIDCREDENTIALS INTERACTIONREQUIRED

Previously, I also received:

UNKNOWN undefined

Current Session ID:

cb411338-c7af-af4S-8cOf-8cbS6d94a611

I have already tried:

removing and re-adding the account,

restarting New Outlook,

resetting New Outlook,

reinstalling New Outlook,

verifying the OVH IMAP/SMTP settings,

verifying the credentials in Classic Outlook.

None of these changed the result.

This looks very similar to the Microsoft Q&A cases from 2026 concerning migrated IMAP accounts where the email address remains the same but the IMAP server changes.

In particular, this case appears highly relevant:

“New Outlook for Windows won't add a migrated IMAP account — Cloud Mailbox stuck on old server (ImapRemoteServerInfo locked), needs service-level reset.”

Another August 2026 case reports the explicit backend error:

Changing the ImapRemoteServerInfo is not allowed

when the IMAP server was changed after a hosting migration.

Could someone familiar with the New Outlook backend please confirm whether the Microsoft Cloud account associated with my email address may still contain the old IMAP server information?

If so, is there a supported way to reset/re-provision the IMAP Cloud Mailbox so that New Outlook can register the current OVH server?

Microsoft Support has already reviewed the case and confirmed that the issue appears to require deeper investigation, but their current support channel does not have access to modify or reset the IMAP backend association.

I specifically want to use New Outlook. Classic Outlook works, but it does not resolve the New Outlook issue.