STILL Cannot Join Any Multiplayer Match (1.0.1.6)

First, I've only ever seen ONE (1) error message in hours of troubleshooting this issue. The following is that error message, and it only showed up in the server browser when trying to connect to a game that way.

Second, trying to connect to a match via the matchmaking method (lobby screen > click "start" at bottom left) has only worked ONE (1) time in my hours of troubleshooting, and it was immediately after uninstalling the multiplayer component of the game and then reinstalling it. Since then, I've tried this again multiple times and it has not worked. I've tried fully reinstalling the game twice as well, to no avail.

Currently, I cannot get the game to show me an error message of any kind, not even in the server browser screen where I first saw the error message above. In the server browser, nothing happens when I click join. No queue at the top of my screen. No error messages. Nothing to tell me it's trying to connect.

Similarly, trying to connect to a game using the lobby's matchmaking does not work. I click "start" at the bottom left, it says it's matchmaking and starts counting. After a few seconds that little button vanishes, my character stands up and it acts like it's going to launch into the game, but it never does, and the "start" button at the bottom left comes back.

This is a $70 game, and I should be able to play multiplayer, which is arguably THE main reason many people like myself play. Please figure this out SOON.