You need to use Apple’s Script Editor to make this change. If you’re not expecting any URL or server address changes, you can force the server URL and disable background auto discover in Outlook. I believe the issue is related to AutoDiscover when having multiple accounts and things get crossed. The issue will usually happen repeatedly. Outlook for MacOS seems to have a sporadic issue when you add multiple Exchange (Office 365) accounts where both accounts will show “Not Connected” at random times and the only way to force a reconnect is to close Outlook and re-open it.