Steam multiplayer is not working on my PC anymore

I had a Steam multiplayer project that was working. Around the time 4.14 preview came out, I updated the project. Multiplayer no longer worked for me. I found a version of the project I hadn’t modified since it was working on 4.13. It no longer works for me. Both versions work fine on other people’s PCs. This seems to be a problem with my PC specifically. I don’t know what to do to go about troubleshooting and fixing the problem from here. Any help is much appreciated. If there is a better section for this to be posted in, mods feel free to move it there. Thank you.


Steam build instructions for 4.13 / 4.14

I should mention that I am still using the Spacewar test app id and I do get a working Steam overlay. I am testing using the packaged project.

I did further testing. I have two PCs in my house, a laptop and a desktop. People outside my home can connect to each other. They can also connect to my laptop. My desktop cannot make any connections. It does not matter hosting vs joining.

Do I need port forwarding? Could my router have been updated and is now blocking the traffic for the specific ports needed?
Could PeerBlock have interfered with this even though I don’t have it installed anymore?