new Exchange Installation Autodiscover

Hi

I have had a lab environment and suspended this to get experience with a new setup. Old setup had a ADFS server in place.

New lab setup is based on Windows Server 2025, 1 DC, 1 Exchange server SE. Installation is ok. Client is a Windows 11 machine with Outlook 2019.

DC is synching to EntraID. All based on German language. GPO for autodiscover is set. As well the DNS records.

Post installation is the part where I am have an issue at. At least in the part of the autodiscover.   Adding the primary mail address is always leading in pointing to the company authentification page adfs.xy.com which was in the old lab in place.

I cant see any DNS entry neither on my external DNS provider nor internal (brand new setup) and have no clou where to search further. Wensearch did also not lead me to any solution. And a workaround to disable autodiscover is not my goal.

Therefore I am happy to get any idea where to look at to get read of the adfs link.

Appreciate your support. THY mame