Need Help With Dedicated Server

Yes Ive seen the setup guide in the sidebar.

My situation: I have a router/modem connected to another router that is then connected to my PC.

I have port forwarded on both routers (and Ive even got PZ to work before, 2 years ago before the dedicated server). I did the ports listed in the setup guide.

Now I cant connect to my own server but weirdly my friends can "see" it if they enter my external IP. It tells them the server version, ping, and population but if either I, or they try to connect it just says failed to make p2p connection.

What is going on?