Using classic Outlook for Windows in business environments
Yep. Did all of the suggested fixes too. Still does not work. For MS to say it is not on their end is BS.
Outlook is simply trying to connect to the server and is unable to find it because MS is no longer equating (in its DNS/routing translation, probably) to allow Outlook to connect to the server in question. Only Outlook 365 is listed (=allowed) for this. It would be easy to list all outlook versions in some file to allow the connection. However, simply stating that MS did not do this is BS. Someone physically replaced the file to establish the new 365 Outlook and did not look back at all the entries in the old file. Definitely a MS Systems Administration blunder. Not willing to fix/look into fixing it is simply to push all the users to use the Outlook 365 which connects perfectly to the mail server (leading customers by the short hairs). Protesting seems to do nothing.
Frustrating...
Retired but not without some ideas...