Why has my Outlook mail suddenly stopped connecting to my MacBook Pro mail app?

It appears that in the short-term this is a Microsoft issue. Microsoft announced on 2/2 that EWS was going away in October of this year, but it seems they may have done something to disable it early for some. Apple's Mail app still uses EWS to connect to M365 while the iOS/iPadOS and Outlook do not. We submitted a ticket yesterday to Microsoft after noticing no EWS connections to our Microsoft 365 tenant took place after Sunday, 2/1. As of this morning (2/5) it is now working again for our customers. In the long-term, since EWS is being retired in October, Apple's Mail app for macOS will need to be updated to use the Graph APIs vs. EWS in order to continue functioning.