AC1900 C7000v2 partial connectivity with Xfinity internet

[GNM638]

I installed and activated AC1900 Nighthawk with Xfinity techsupport by telephone today. Everything seemed OK except I could not use Chrome or access gmail from my HP desktop Windows 10 computer nor could my LG smart TV connect to the internet.  Microsoft Edge had no problem finding various frequently used websites. I cleared the browser cache for 'All Time' but still had the problem. I spent over 2 hours this morning with Xfinity tech support; I really appreciate the agents patience while I described the spinning circles on the computer screen or TV. I attempted to activate the modem using the routerlogin but that failed and was contacted by the Xfinity agent by cellphone.

I'm wondering if their is a hardware firewall built-in to the Nighthawk causing the comm problem. I didn't try using the Nighthawk App for Android after reading a bunch of reviews during the installation of the app. I have not tried contacting Netgear phone support.

[FURRYe38]

Any Wifi Neighbors near by? If so, how many?

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem for 1 minute them back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...