Fix Outlook Outbox Issue on Mac

I need assistance troubleshooting an Outlook issue on my MacBook Air. Emails are getting stuck in the Outbox and only send after I restart Outlook or my Mac. This problem affects my Microsoft 365 account and occurs with every email, even simple text-only ones.

Ideal Skills and Experience:
- Expertise in troubleshooting Outlook on Mac
- Familiarity with Microsoft 365 integration
- Experience resolving email sending issues
- Ability to diagnose and fix software bugs

A quick and effective solution is preferred. Please provide your approach and estimated timeline.