Hello @Trraash sorry to see this error code affecting a disruption in your gaming sessions. I can recommend to complete the rest of the steps in our connectivity guide here to include forwarding the port ranges that are specific to Rainbow Six Siege. A few players have also found good results with the workaround below:
- Locate your 'GameSettings' configuration file in the game's directory. Commonly your game will install the file at the location Documents\Rainbow Six Siege\GameSettings.ini
- Open the 'GameSettings' file and change the "UseProxy...