Error message while trying to host a coop-server "Your connection to master-server was temporary lost. Check your internet connection."

[ahmenvafaan]

Hey,

 

I've followed the steps in this thread:

 

But when trying to host a server I get the following error message:

 

"Your connection to master-server was temporary lost. Check your internet connection."

 

Anything I might've missed? Running out of ideas here ?

 

Thank you in beforehand.