So I have two 750s. One is being used as a wireguard server that connects to my ISP Router the other one is used as a client, connecting to the server.
On the client side i have configured the firewall settings as such:
Try changing reject to drop, if you do want to play something. The difference is that, when someone want to connect to your server, drop will not give him any reply, so he does not know if your server is online or not.