Activate Modem - problem with xfinity app

I have managed to sign in to the modem using 10.0.0.1 and to get internet service and wifi. However, when I try to use the xfinity app to modify the SSID and wifi password, the app just loops between a sign in screen and a screen that says I am already signed in. How do I get the app to behave the way it is supposed to , or otherwise access the modem features?