Why won't my game consistently work online?

I’m using a 4.8 Release from Git HUB to make a dedicated server which I had working properly on a windows PC with an open port. For some reason it’s only working locally now and not with online. Let me elaborate:

Working: connected to the internet on the same router using the static IP from the computer. The game works fine and a full round can be played with no problems.

Not Working: connected to an internet other then the routers and using the IP currently on the computer with the server. The game plays perfect but after a while the Remote Procedure Calls (RPC’s) invoked by the server stop getting to the client with the other internet though the RPC’s from that client still get to the server and get to the other client.

I’ve spent day’s on diferente problems but this has me stumped. I had this working perfectly before from PC to PC.

Any ideas what could be going wrong?

thank you!

Well I was talking to a friend of mine who spoke to router, networking savvy gentlemen who told me the issue does not sound like a programming issue but instead a ip conflict issue, so I tried the game with one on local where the server was and the other on the external IP that forwards to the inner ip and everything works now, even from cellphones and tablets.

Now all I have to do is figure out if it can work with two devices external to the router but this solves my issues with the game for now.