R6220 - Trouble connecting PlayStation

I'm having trouble connecting my PlayStation 4 to the internet.  I have a cable modem connected to the R6220.  Every other device on the network seems to work just fine (computers, tablets, phones, etc).  But I'm having trouble with the PlayStation.  I'm usually able to start up a game and play for a minute or two, but then I'm disconnected.  Do you think this could be a router issue?

I've tried updating the firmware, turning UPnP on and off, setting up port forwarding, and setting the default DMZ server.  Nothing seems to help.  I also called the cable company and they said everything looks fine on their end.  Any advice would be greatly appreciated.