You can check your "More Info" screen by holding down INFO button 5 seconds and scroll through till you see STB port, status, and audio. If you see a paired number like 27161 (STB) and 27162 (Audio) and a status GT 5000, it's working but there may have been a connect error. It happens frequently at initial setup. You can use those numbers to forward port. They should be paired starting at lowest number or at least that's how your STB's will try to setup.
It's best to try to wait an hour or up to a day to try reconnecting. If you keep trying to force the issue in Automatic mode with multiple boxes on your network, you're likely to confuse it and they will try to swap ports or increment but never stay with the numbers you're trying to assign. I've actually had more success by leaving it alone and coming back in much later and it works without the fuss.
Nonetheless, if you see the status number changing, it's actually working and could be left to sort it itself out. Like you say, it's getting all the features, most likely it's saying "Network Services has started but connection test failed".
I've found that it's a must to forward ports if you're not using a switch between the router and STB. After installing my switch, I seem to have more success in Automatic Mode if I don't force the issue and cause it to keep changing the port numbers.
Manual mode works well for router with forwarded ports but Automatic seems best IMO with a switch. Maybe best to setup network services one at a time but at the same time, know what default port for each STB on network is.