[SOLVED] Difficulty With Minecraft Server

This is yet another "cant set up a Minecraft server" post ... Minecraft crafting Hoping someone will be capable of helping. The server works on my machine but it is not working on his.

Our computers are connected via ethernet cable directly to the ASUS RT–AC86U router. His IP address local to the United States is 192.168.50.166.

The port forwarding settings are:

Service Name Minecraft Source IP (blank). Port Range: 2565 Local IP: 192.168.50.166 Port: 25565 TCP : BOTH

He connects to 192.168.50.166 when he is running Minecraft from his own computer. However when he enters an external IP (obtained via the "Network Map" page of the router's settings) it will give the following error message:

Failed to connect to the server io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection timed out: no further information

I get the same error in Minecraft when I try to connect to 192.168.50.166 from my own computer.

But here's the kicker ... Everything works if I run the server on my personal computer (192.168.50.48) and alter the Local IP port forward settings according to my needs. I can connect to the Minecraft server using either my local IP or an external IP.