Using Nighthawk R7900P With FioS WAN Connection

Hi all! I recently picked up a previously owned Nighthawk R7900P router that I am trying to get set up with my Verizon FiOS internet. Unfortunately the router is not cooperating. It’s weird because I have used a number of other Nighthawk models without trouble. I connect directly to the FiOS ONT via Ethernet, there is no modem in my setup. On every other model I’ve used it’s as simple as plugging the Ethernet cable in and that’s it. The router setup wizard does the rest. Not with this router, it absolutely cannot get connected. I find it hard to believe that this model lacks WAN capability. Maybe there’s extra steps for this model or something? I’m truly stumped, any help would be greatly appreciated.