If you’re having trouble finding your friend’s game when searching for servers - even though you've setup a unique server name - then have the host and client/s set their Steam region settings to the same region.
This can be changed in Steam by going to:
- Click on ‘Steam’ from the header and select ‘Settings’
- Under the ‘Downloads’ tab, select ‘Download Region’
- Make sure you are running the same region as the host
- You should now be able to connect
Edited by Neil Brock