[2021] When i start a coop game with my friend, and we quit, when we try to enter again, the game just freezes

Alright. Since you mention this is happening recently, could you try adding the following line to ConanSandbox\Saved\Config\Windows\Engine.ini

[/Script/ConanSandbox.SystemSettings]
dw.UseModControllerCache=0

Please let us know if that helped you.

Another question, just in case: does the game freeze when trying to play on a dedicated server?

Thanks for the confirmation. We’ve sent note to our team to see if we can replicate the issue on our end.