NETGEAR Modem not fully responding to Comcast signal

Equipment: NETGEAR - Nighthawk 32 x 8 DOCSIS 3.1 Voice Cable Modem

I recently moved and had Comcast activate my internet and TV services. I was using this modem, paired with the Nighthawk XR500 router at my old apartment, and everything worked perfectly. I ended up having a Comcast Xfinity technician come to help set up everything.

However, the modem was receiving signals from the coaxial input, but would not distribute any internet to my router. The only success we had was by connecting an ethernet from the modem to a laptop and we could surf the web just fine.

I tried connecting from the modem to a gaming system using ethernet, but it would not work.

The technician that came to my home spoke with another technician on the phone and they still could not figure it out. 

They ended up setting up an Xfinity modem-router combo just so I could have internet, and said to get a new modem if I wanted.

Does anyone have any ideas? Firmware update? It is just odd because it was all working at my old apartment a week ago, but not at my new house.

My XR500 router does work with the Xfinity modem-router combo.

Thank you.