Other players cannot join my server

[Gilbertz]

So far my server has been working fine, I've been able to log in, and there hadn't been any issues using it or setting it up - until I tried to get someone else on it by making the server public.
I've configured everything correctly (to my knowledge) with my internal IP address, forwarded the ports to my router by using a specific guide for my router type and WoW, etc. but when he/she tries to log in, they get stuck at "Connected," which then moves on to, "Unable to Connect," or (if they have my external IP address in realmlist.wtf) they get to the realm list and cannot move on from there.
I have a static IP and have made the ports exceptions for Firewall, but they still can't log in.
Unsure as to what could possibly be wrong.
I've checked with a program to see if the ports were "open" and, surely, I get a positive result.
Any advice?

[TarridoN]

Have you put your internal IP where it supposed to be and everything? And if you want to make the server public for the the rest of the people i suggest use no-ip. But yeah hthere should be a tut on YouTube for it, follow their steps.

[TheChosenPessimist]