I have the game on Gog, most of my friends have it on steam. We played previously with direct connect without any problem.
Starting a new run today i am unable to change my direct connect settings. It just fails. Is this a known bug?
I have tried verifying the integrity of files, no firewall is blocking any connections.

I also have this problem, so far I have not been able to find a solution.

I too have this issue. Couldn't find any error logs describing why it fails. Reboot the PC and sometimes it allows direct connect.

I tried launching straight from the DoS2 install folder and direct connect worked first time. However, Invite Players doesn't work for GOG mates since I didn't launch it from the GOG launcher.

I found a support article that recommended putting a bunch of galaxy executables in your "security software exceptions". I added them to my firewall exceptions and still no connect. (Windows 10)

I rebooted the PC and direct connect now connects.