What do you do when all the app does is show a screen saying "We Need an Internet Connection"

Yep. It also says:

• Connect to the Internet using a cellular or WiFi connection then select Try Again.
• If you don't hae internet access and are trying to activate your Gateway, follow the printed installation instructions or call 1-800-xfinity

Isn't the whole idea of the app is to get things done without having to call customer service, "...no technician needed?"  Nope.   "Check network status." Nope.  "View your plan details." Nope. "Pay your bill." Nope, nope, nope....

I get the message on cellular and on WiFi.