Verizon ONT to xfi gateway?

I recently signed up for xfinity home internet and just received my router. I just realized that the home I am currently leasing does not have any coax ports - it only has a Verizon ONT (optical network terminal) built in. The ONT has a coax port on it, but when I connect my xfi gateway to it, the gateway isn’t connecting to internet. Is it possible to troubleshoot this, or do I need a Verizon router instead? Please offer any suggestions or ways to approach this. Thanks!