Just migrated some accounts from an on-prem Exchange server to O365. Some of those accounts need IMAP access. IMAP access is turned on for those individual mailboxes in the cloud Exchange control panel, but it's not working. Pointing the client at the outlook.office365.com server for IMAP just comes back with bad account/password on the e-mail client. Is there some other setting on O365 that needs to be turned on for IMAP to work? Username should just be the e-mail address, correct?
You have multi-factor authentication (MFA) enabled. IMAP doesn't support MFA.
Your users need to create separate App Passwords for IMAP on https://account.activedirectory.windowsazure.com/AppPasswords.aspx
This would probably have worked without enabling IMAP for individual users.
By default, POP3 and IMAP4 are enabled for all users in Exchange Online. You can disable them for individual users.
To be complete, you also need correct IMAP & SMTP settings:
- SMTP submission:
From Microsoft 365 admin center find necessary user-> disable 'Authenticated SMTP' option, save and after 3-5 minutes enable again and save: see picture