Hello. I've recently set up my own server with port forwarding, and I've tested it out on my laptop and it connects just fine. However, when my friend tries to connect, it says "connecting to...." but nothing happens. Anyone know why?

When I try to port forward for BO2 Zombies, it only asks me for a port number and a protocol. When I switch it to UDP and put in the port number: 4976, it says error. Anyone got a solution?