I went through all the steps I could find to get it to connect but on 26/12 at about 2AM GMT it lost connection and I haven't been able to connect since. It also doesn't work for 5 other people I have talked to, but I couldn't find anything about server downtime so I thought it might be a region thing as we are all in Australia or New Zealand.
Any help is appreciated, thanks.

Same, I've been trying to fix it for the past 3 months but its just not working.

It works fine on my machine (windows 7).

Application is whitelisted or firewall is off?

Give us some more information what you current situation looks like: Firewall, Anti-Virus / Malware Application, Operating System

Was just about to post 1000 word report of everything i tried to get it to work but you saying you used win 7 got me to try running it in win 7 compatibility mode and it worked. Something must have changed in win 10 and 8.1 that breaks it.

This might also be why UGX 1.1 maps stopped working regardless of weapon sway settings but for some reason i can't change cod waw compatibility settings or steam can't launch it due to an app error but thats another issue.