Posted 02 September 2012 - 03:04 PM
Are you using your own router in addition to the Uverse router? If so, then you're likely in a "Double-NAT" situation, which means that both routers would be trying to provide Network Address Translation, causing specific network traffic like we need to not be able to get through. In that sort of situation, the general solution is to decide which of your two routers you want to act as the 'brains' and then go into the other router configuration and turn off NAT by putting it into "bridge mode" (it's possible it may be called something else, though).
You'll also want to make sure that 'uPnP' and/or 'NAT-PMP' features are enabled in whichever router you decide to use as the brains. That can help allow for automatic configuration, which means you would go uncheck the "Manually specify port" option in the Plex Media Server myPlex preference tab.