Well i just saw that in front of our firewall there is another firewall which i dont have access on :(
So no coop-games at work :( ^^
Ty for help anyway and sorry for wasting your time.
Have a good day.
Na. Its something on our firewall. If i take another gateway its working.
The Problem is, if i take another gateway i can't manage ports and portforwarding :(
Well atm i'm trying to launch the game.
The Gamescan gives error 403.
If i try to launch the game i get error message Login to Celeste Fan Project failed.