https://docs.microsoft.com/de-de/exchange/architecture/client-access/autodiscover?view=exchserver-2019

AutodiscoverURL sollte diese sein:
https://mail.contoso.com/Autodiscover/Autodiscover.xml

Der DNS - SRV-Eintrag müsste dann wie folgt aussehen:

* Service _autodiscover
* Protocol _tcp
* Priority 10 (or as per your design)
* Weight 10 (or as per your design)
* Port 443
* Target mail.contoso.com