AutoDiscover Issue with Exchange 2016 iApp

Hello together,

 

got one big problem:

 

I have deployed successfully the iApp template of Exchange 2016 and the customer wants to use OWA and AutoDiscover Service.

 

The AutoDiscover Service is not working as expected.. so the user cannot authenticate with e-mail or domain\username.

 

My Access Policy: Logon Page (Split Domain from full Username YES) -> AD Query (Cross Domain Support DISABLED) -> AD Auth (Cross Domain Support ENABLED) -> SSO Credential Mapping (default).

 

I used the right Domains and Access Profiles. OWA is a logon possible with E-Mail, User and domain\User. But AutoDiscover is just User and domain\User. E-Mail is NOT working. Does anyone know, how the users could finally authenticate via E-Mail? They're claiming that they're not able to use AutoDiscover

 

Thanks in Advance!

 

Hank