Another Remote Access Problem

Hi,

I've been trying to get the remote access feature to work for (on and off) two plus years at this point. Here's what I can tell you:

1. It's not double NAT
2. My cable modem / router is a SBG6580
3. I've had UPnP both enabled, disabled and I've tried toggling it on and off.
4. The router firewall is off
5. I've created a static local IP for my server.
6. I've manually specified a port for Plex through the router's software.
7. I've tried a variety of ports for the Plex media server, including the ubiquitous 32400
8. Externally, canyouseeme.org times out when checking the specified port. Other software reports the port is closed.
9. I've tried to put the server in the routers DMZ with no change
10. I've futzed around with the Windows firewall setting to try to make this work, no success.
11. My ISP is Comcast.

At this point I'm just a little tired of doing this for so long with absolutely no success. If anyone has any suggestions or advice I'd be most appreciative.