G20 dropping connection

I set up my G20 gateway (wifi router and modem combo) and it keeps dropping the connection periodically. Anywhere from every 5-20 minutes or so, it will suddenly cut out and I’ll lose internet access. I had to set this up through xfinity as the app didn’t work so I can’t really use that to see if there’s anything that stands out on the surfboard app. I’ve checked the coax cable and it seems fine and it was functioning properly with my last modem. I’ve done an internet speed test and when it’s working it says my internet is very fast.