Storm Ready Wifi unit causing connectivity problems

I received the Storm Ready wifi unit at the end of June.  Took hours to get the thing up and running with my Gateway, but it finally worked after just leaving it alone.  It has been running a little over 2 weeks and over the last 2 days, devices have not been able to connect to internet.  Started with a single Ring camera, then iPad, laptop computer and iPhone.  iPad and computer would get error message that can't connect and when you try to connect manually, it says the password is incorrect. But if you bring the iPad/computer next to the Gateway, there is no issue.  Last night another Ring camera went off line.  Rebooted Gateway via the app, same problem.  Unplugged the Gateway to reboot, same problem.  Finally disconnected the Storm Ready wifi unit, and all my devices have no problem connecting.

So, at this point, the Storm Ready wifi unit is boxed up in a closet.  Should I bring it back to an xfinity store?  Or do you have any know fixes for this problem?  I do not want worry that I this will happen again with the unit on line and devices stop working especially when I am not at home, since I do have a security system tied into all this.