Removed all MS-related entries under Keychain AccessĬompletely reset outlook (Terminal: defaults remove com.microsoft. On Windows, this problem can occur as well but it can easily be solved with the registry setting 'ExcludeExplicitO365Endpoint', which doesn't seem to exist on macOS. It doesn't matter if we enter the correct password or not, it shows up every time. We cancel the 365 sign-in prompt and the account is successfully set up.īut unfortunately, the 365 authentication prompt (username suggested: reappears at every Outlook launch. At the same time, the AutoDiscover confirmation prompt appears, which we accept.

When we try to add said mailbox in Outlook, a modern authentication dialog is shown. The affected user has a mailbox with the UPN and mail address which is hosted on said Exchange 2019 organization. There are no Exchange Online mailboxes at all in this tenant, because they've got On-Premises Exchange 2019 (DAG).

Make sure it works elsewhere, and make sure youre typing it in.

Outlook is activated through an AD synced Office 365 account with username This account only has an Microsoft 365 Apps for Enterprise license assigned. The bottom line is simple: most of the time, the problem is just getting the password wrong. We have a Mac with the newest macOS and the most recent Outlook version v16.66 (it's evil). All Mac users prefer using this application for their office, college, personal use, and many other fields of interest. I've just wasted 2 hours trying to resolve the following problem:

Office mac keeps asking for password