RM6500 AT&T. My Android gets the message that it is connected, but it is a "Limited Connection"

I'm not sure if this is the right support board, but here goes.

I am having trouble with my RM6500. We recently signed up with AT&T and at my local store's recommendation purchased this "refurbished" unit through Amazon.  My Android internet connection gets the message that it is connected, but it is a "Limited Connection" and none of my devices work. The first M6 Pro we bought was overheating and shutting down so we returned it and we are not now having these problems with this second M6 Pro. I have checked the firmware and it says it is up to date. I am using AT&T for my internet data and have lots of devices in my home. When it's connected the signal seems strong and Speedtest.net says I'm around 35mps.

Is this normal behavior? Is there a better modem that I could use with AT&T?  Should I return this unit through Amazon and just but a new one directly from AT&T?

I see some helpful people requesting the .json file, whatever that is, so I'm attaching mine.

Thanks.