Dungeon Defenders - Can't join friends' games (no attempt, nothing happens)

I understand there's a bug where I can't join friends' ranked (Trendynet) games unless I am also logged into Trendynet. This is not that.

After logging in, when I try to join a friend's game (shift+tab --> friends --> click the down arrow next to the friend's name --> Join Game), nothing happens. It doesn't attempt to join the game, I don't get a "failed to join game" message - nothing. However, they can all join my private game.

Does anyone know how to fix this problem?

Solution 1:

Apparently, this happens when you (the player trying to join) have filters for custom games set.

To reset your filters:

• Log into TrendyNet
• Click "Custom Game"
• Click the "reset" button in the lower-right.

You should now be able to join friends' custom games.

Another solution that solved this intermittently for me (perhaps differing versions?) was to have all players (including the host) reverify their game-cache.

To reverify your game cache:

• Close out of Dungeon Defenders
• Right-click the game on Steam --> Properties --> Local Files --> Verify integrity of game cache.

Every time you do this after playing, you will get "Two files failed to validate. They will be redownloaded," even if there's nothing wrong with your game.

However, this fixed the problem for us a few times, before we knew about the custom-games filter solution (and before I had any filters set...).