Can't open ports on router 5268AC

I solved the problem. The problem was that the emulator has a Port Offset of 10000, so I had to adjust the ports adding that number to the port I wanted to forward, for example: if I need to forward port 20001, I have to add 10000 to that number and forward the port 30001 because that is the port the emulator will use. 

Thanks @JefferMC for your time trying to help me.

The emulator is up and running when you do these port scans?

Have you done a netstat -a on your host and looked to confirm the listening port is there?

@JefferMC yes the emulator is up and running when I do those port scans. I just did netstat -a and I don't see any of the ports there.

Hmm... if you can't see the ports in your netstat, the question is if the software is working as you expect.  How are you running the emulator?  Is it in a VM, a container, etc?

Another way of validating your ports is to try to access your emulator from within your own LAN using the private IP of that node and the port.

@JefferMC the emulator is working fine. I can see players in the Match making room but if I host a match they get disconnected probably because the ports are closed. I don't know what a container is but I installed the emulator in my pc not on VM. There are some players that host the match and I don't get disconnected, because their router have upnp or because their ports are open.

Let me see if I understand:

1) You run the game server in an emulator on your PC (or is it that the server/emulator are one thing)

2) You can host the game and you can connect to it from your _______ (PC, Console) game client, but when others try they can't.

@JefferMC please read this guide, It may help better than me to understand how the game and emulator works online. PPSSPP Monster Hunter Multiplayer Guide (google.com)

Okay, now I understand.  You're running a PSP P2P game within a PSP emulator on your PC.  Your PC has to accept communications from up to 4 other players on TCP via different ports.

You can load the game and the match maker can see your request, but nobody can play in a game you've joined because they can't get to you.

If you enter ()

netstat -a | findstr /r /c:"^  TCP    0\.0\.0\.0:2000. "

and you should get back

 TCP    0.0.0.0:20001         compname:0        LISTENING
 TCP    0.0.0.0:20002         compname:0        LISTENING
 TCP    0.0.0.0:20003         compname:0        LISTENING
 TCP    0.0.0.0:20004         compname:0        LISTENING

If that's not what you see, then something's not right with the emulator.

Assuming you do see that, the emulator is opening the ports.  You say you turned off Windows Firewall?  Got any other security software that might be running a Firewall?

@JefferMC I don't see that if I enter netstat -a in CMD. I doubt the emulator have issues. How do I test if the router actually open ports that I open?

@JefferMC they have a wifi extender at home. Could that be the problem? but I'm connected directly to the main router with ethernet cable.