Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - Bugs & Technical Problems Multiplayer loading stuck at 80%

I found a possible solution for the problem:

Enter the command "netsh winsock reset" into the command line (or Powershell) as Administrator and reboot the PC afterwards.

After my friend (the host) ran this on his PC, I was able to join his game again.