Virtual server port forwarding?

I have a linux machine that I use as a server running Apache2 (it works perfectly fine locally), and I want to use port forwarding to access it from the public ip address.

I tried using the router's virtual server service, so I redirected my local to port 443 of my public ip address, I already used http://www.portchecktool.com/ to scan the port, and it says that the port is open whenever I enable it (I tried changing the port number many times, 443, 22, 5555...). But when I try to connect, it says 'Unable to connect'. (Even thought the port scanner tool says the port is open on my public ip, when I scan my router's port with nmap it says it's closed)

I know I didn't provide many details, but is there something that I'm missing ?