IOS Notifications don't work

Hello,

We have the Sophos Mobile Controll with the Sophos Mobile Mail running in our company.

Settings are: Privat Device and Container Mail solution, Users Added with Active Directory.

Everthing is working but not the notifications for IOS.

-I already did these things:

https://community.sophos.com/kb/en-us/131681

-Push notifications are activiatet on IOS under Apps -> Permissions

And

-https://community.sophos.com/kb/en-us/127137

But here we added EWS only for two test IOS Users and we did not activated the Basic Authtification.

Did I forget something? Or does it only work when I also activate the Basic Authtification in the IIS?

Thanks for your help!