Why is port 2121 "closed" when netstat says it is Listening?

Why is port 2121 "closed" when netstat says it is Listening?

I'm running iis 6, and I created two ftp sites. One is running on port 21,
and it works just fine. The other is running on port 2121, and I did all
of the following: 1) I opened port 2121 in my firewall (even turned
firewall off completely). 2) I bound my new ftp site to port 2121, and it
shows that 2121 is bound by it. 3) I ran a elevated cmd prompt and typed
netstat -a and it shows port 2121 is "listening". 4) I browse on the local
system to ftp:// localhost:2121and it goes straight to the FTP server, no
problems.
Yet when I try to go to the ftp server from a computer that is connected
to a different internet provider (aka, my cell phone), it times out trying
to connect. When I go to any port checker website and tell it to test to
see if my port is open, it says "port 2121 is closed" on my site. Huh?
Netstat says it is "listening"?
So I tried also binding port 5999, and that times out too.
My "site" is a hosted VPS server provided by myhosting.com, so I trust
that they wouldn't be blocking any of my ports. That should answer your
questions regarding whether or not I am behind a router that isn't
forwarding the port.
Any help would be appreciated.