This is a recent bug that was introduced as a result of changes to how Steam handles player lobbies. It affects everyone. It causes friendlies lobbies to be blocked in many cases, and prevents you from queuing against a significant percentage of other players on casual/ranked.

No one player is blocked from all matches, nor are blocks permanent — effectively, random pairs of players will be unable to matchmake with each other for random amounts of time. Again, this affects all lobbies (casual, ranked, and friendlies).

This bug wasn't introduced by a patch to the game — like I said, Steam's changes to how lobbies work is the culprit. This bug may be fixed eventually, either by Steam or Aether Studios, but for now, this solution is the best way to handle it.

It's pretty simple. Just make sure you have Steam closed for this (don't simply close the window, but right-click it on the taskbar and click "exit Steam," or open Task Manager, select it, and click "end task") or things might get messy.

Also, make sure you have Steam Cloud turned ON and give it time to download your game data if you didn't have it on already. Otherwise, your game files may revert to earlier versions, since Steam pulls from SC to restore many files.

- Go to your steam folder (default directory for Windows is C:\Program Files (x86)\Steam)
- Select everything besides the steamapps folder and steam.exe executable (easiest way is to just Ctrl + A and then Ctrl-click those two to deselect them)
- Delete the selected files/folders
- Reopen Steam

The steamapps folder (along with your AppData/Roaming folder, outside of the Steam folder), contains your game data; steam.exe is your way to launch the app, so it's important to keep those around. Everything else should regenerate once you relaunch Steam, as every other file is either automatic or can pull data from Steam Cloud (I think) — but if you have Steam Cloud turned off, it may revert to an old version (i.e. whatever is most recently uploaded to SC).

Workshop content, mods, game settings, etc. should not be affected, as that's all in the steamapps and external AppData/Roaming folders.

I know this sounds pretty dangerous, so you'll just have to trust me. This bug has been a big thorn in the side of competitive players (two specific players being unable to connect causes obvious problems for tournaments), and this fix has been widespread in that community for a while. As far as I've heard, nobody's ever suffered any averse effects from it. If you DO run into any negative side-effects of doing this, please let me know in the comments.

If you'd rather not take the risk, you can back up your Steam and Roaming folders (which I advise doing regardless) by copying them somewhere else, and if anything gets messed up by Steam Cloud or in any other way, you can just copy them back. You can also just not do the fix, which means you have to deal with the consequences of the bug.

MOLLO ♥♥♥♥♥♥♥ RULES GRAHHH