Strange Login Behaviours

[Metamagixx]

Hello toghether,

we have a very strange qlik behaviour regarding the login.

The Server on which Qlik is installed in an Active Directory and if I'm on the Server I can login to qlik with

https://localhost:9443/qmc  (or hub)

or

https://ipadress:9443/qmc (or hub)

but not with 

https://Domainname:9443/qmc (or hub)

From a Client or an Other Server it is possible to Login to

https://Domainname:9443/qmc (or hub)

Is this any special behaviour I can configure somewhere? 

Thx a lot for helping.