I am cross-posting this from the QNAP NAS forum, as I believe the issue is actually with the router (Fios G1100):
I recently attempted to activate the VPN service on my QNAP NAS (TS-251, latest firmware). I used the NAS auto router configuration/UPnP to apply the port fowarding settings. This worked, and I was successfully abIe to connect with my phone to my home network via VPN. The next day, however, the VPN wouldn't connect and looking at the UPnP menu page, all the ports have connectivity errors. I then disabled UPnP and tried to manually open port 1194 for the VPN service - the port forwarding rule appears correct (192.168.1.241:1194 // Destination Ports 1194, TCP Any -> 1194, UDP Any -> 1194), but there is no connectivity to the VPN service.
I am now wondering if this is a router problem - when i check for open ports (http://www.yougetsignal.com/tools/open-ports/) port 1194 is listed as closed (as are all the other ports that are failing in my NAS UPnP menu). Meanwhile, I am still able to use remote desktop, and port 3389 is indeed confirmed as open.
Am I missing something? Try a hard reset of the router? Any help would be greatly appreciated! Thank you