Hosting/Joining Sessions with Steam

I recently started trying to make a multiplayer game using Steam and UE4.27.2. When testing out the connection on my own machine, it works fine (over LAN). After copied the entire project and replaced some folders with the exported version, I tried to run it on another machine. The machine has Steam, UE4.27.2, Steam is running, and of course a copy of the project. To test it, I had the original running on the first machine, with a match being hosted. In other words, I hosted a session, and it should be visible. It was not visible on the second machine, and I could not host a session, nor find any other sessions, on the second machine. Does anyone have any idea why? I saw that 4.27 was supposedly broken with Steam, but I thought I saw a hotfix saying it was fixed. I’m at a loss. Both machines have the same exact project files, and both are running Steam, but only the first can host, and the second can’t find the first’s sessions, nor create its own. Any advice is welcome.

Yes, I have searched for things about this for well over an hour or two. Nothing worked, or it didn’t really pertain to my problem. I also tried packaging the game and running the packaged game on both machines.