nighthawk ax6 rax50 randomly disconnecting

       Hello, my family recently bought a duel router setup, the nighthawk ax6 ax50 V1.0.2.66_2.0.42, and arris surboard sb8200, and we have Comcast internet. We previously had a xfi router that cut out pretty often. We expected the new setup to be way better. The internet goes down atleast 10 - 12 times a day and for around 30 - 1min intervals for the past 3 days, it was down once for 2 hours even rebooting and power cycling. I've called Comcast and said it was nothing to do with with the internet it was the nighthawk router. We've tried multiple troubleshooting options like, " Rebooting, Power Cycling, and Updating the firmware. " I would really like it if anyone can help ASAP. Thanks!