1. I've tried running the server with Avast Firewall turned off.
2. Tried the same with Windows Firewall and Avast Firewall turned off.
3. Tried the same with Avast uninstalled and Malwarebytes turned off.
4. Tried the same with basically everything related to security turned off.
5. Went through the trouble of installing the server files on a completely different device, forwarding the ports for said device and STILL no-one can connect.
After spending a few hours tonight and a few hours yesterday basically exhausting all possibilities I could think of I am still having problems, so I can only conclude that it is the router giving me problems. It's odd because for about a week before this happened I had absolutely no problems with people connecting, this problem only just started yesterday.
So if it is the router what sort of things can I do to hopefully solve this problem?
NOTE: As I mentioned I did forward to correct ports and I also setup a Static IP for both my PC and my Windows Tablet. I seriously can't think of anything else that could be causing it.