[2020] Backend error: Failed to receive data

Did you try to contact support? You should create a ticket for this issue.

I also recommend the following (although I doubt it will solve it but worth a try):

Try closing the game, restart your computer, reboot your router, then launch the game again. In some cases, antiviruses prevents some files which cause this issue, you may want to exempt the game to your antivirus and firewall. Run game as admin.