I would have to call this on a firmware bug, unless that Error is also suggesting a faulty Coaxial connection. Try setting the DNS Servers of 220.127.116.11 and 18.104.22.168 on one of your PCs. When the router gives that error, check the PC with the custom DNS entry on it to see if it is still able to resolve domains and transfer data, whereas the other PCs are unable to. If your PC is dead in the water despite the changes, I would take a nice look at the MoCa link between the router and the ONT; perhaps a splitter or cable might be going bad. Otherwise, I'd have to call it on a Firmware bug if replacing it with an ActionTec fixes the problem.