System Notification to Agents with M365 not working

Zammad version: 5.2.x
Zammad installation type: package
OS: Ubuntu 20.04 LTS
Browser: Microsoft Edge 106.0.1370.34

Hello together,
we are new to Zammad and have a problem with the system notifications to the Agents.
We sending Mails over M365 oAuth2. Mails to customers and triggers are working without problems.

But our Agents not getting any System notification (New Tickets, status change, etc.)
In the Agent profiles the Email notification is set.

Is this not working over M365? Do i really need Mail configuration with SMTP?

Thanks for your help

Please see this thread which is a technical duplicate (no worries):

Additionally you can learn more about Zammads notification channel here: