DECO S4

I have DECO S4 mesh. I just got Xfinity Router/Modem. If I change the S4 to Access Point I lose the internet on the S4 system. I have rebooted both and no luck. I reinstalled the Deco and no luck.

One other thing the Xfinity IP is 10.0.0.1 and the Deco is 192.168.68.01 if that helps.

Any help would be greatly appreciated.