Outlook trying to autodiscover server that no longer exists

Autodiscover seems to have a lot of similar issues, but this one case existing solutions don't seem to help...

Has the common "Allow this website to configure server settings?". However, the server listed below is a server that was removed years ago. The alert is popping up suddenly on a computer (which has been in service for over a year now without having popped this before) that wasn't even around when that server was in production...

There are no autodiscover settings in DNS for that old server. I've verified that they only point to the correct new server. I've done registry "find" on the incorrect server name and also have come up empty.

This is just he latest occurrence of this, it's not a one-off event. It's not been one specific user or PC over the years. Previously I wrote it off as something cached locally as the computers were old enough as they may have been around when the old server was in production. However, now I have one where that definitely is not the case.

Solution 1:

Make sure any public/private DNS record for autodiscover.domainname.com got the same information, the correct IP for your autodiscover to work.

As for me it seem most likely a DNS error.

If the problem occur from the public side, make sure any redirection in any router point to the correct server.

Keep in mind that if Outlook can't resolve autodiscover.domainname.com it failback to try with domainname.com directly. Such request could easily backfire if you have old server in your DNS's console for your parent domain.