Port Forwarding Won't Open Ports

If you are using a Comcast rented gateway device,  try disabling the Xfi Advanced Security feature as a work-around for now and see. It's buggy ! ;

https://www.xfinity.com/support/articles/using-xfinity-xfi-advanced-security

I am having this problem too.  Ever since yesterday night (9/23) all ports are closed.  My firewall on my PC is off and the firewall on my router is off.  In fact, when a port scanner is able to distinguish between a port that is closed but visible and one that is not visible (such as the scanner at www.grc.com), it reports differently depending on whether the port is closed on my firewall--a port closed by my firewall can't even be seen, while one that is otherwise closed is closed but visible.  So it is definitely not th firewall doing it; Comcast has just closed all the ports.

I am not using a Comcast router either.

It seems to be working for me now.

Edit: It seems to have been my error anyway, under a set of multiple circumstances:

-- At one point I wasn't running anything using the port, so it's going to show up as closed no matter what.

-- One of the programs that was using a port just didn't work properly and always reports closed even if a port checker shows it as open

-- Another program that seemed to not have a port open because there weren't any incoming connections eventually had some incoming connections, after a long time.

Wonder how the original poster is making out ?