Microsoft has begun turning off basic authentication (basic auth) for specific protocols in Exchange Online. You will notice this if you are still using basic auth, and your Office 365 connector and associated jobs are failing. Microsoft is disabling basic authentication access for MAPI, RPC, Offline Address Book (OAB), Exchange Web Services (EWS), POP, IMAP, Exchange ActiveSync (EAS), and Remote PowerShell.
Microsoft has published a September 2022 Update that includes instructions on how to request a One-Time Re-Enablement - please see this blog posting:
If you are ready to switch to modern authentication, there is a knowledge article on instructions on how this can be accomplished: Modern Authentication Microsoft.