Unable to join an online game is an error that occurs in Trine 4, which makes it impossible to play multiplayer, invite friends to your game and host games. Many Trine 4 players suffer from it.
There is a quick fix for “Unable to join an online game” error in Trine 4.
Fix 1: Verify Integrity of Trine 4 Files
- Go to Steam Client.
- Type “Trine 4” in the search box.
- Right-click on Trine 4 and go to its Properties.
- Switch to Local Files tab in the top navigation bar.
- There is a button named as “Verify Integrity of Game Files” in Local Files tab, click on it and wait for Steam to verify Integrity of Trine 4 game files (It may take some time).
Now you can launch Trine 4. There will be no more “Unable to join an online game” error 🙂