The Cisco DPC3939 is not compatible with the xfi at. In order for the app to function properly, you will need to upgrade to one of the following devices:
If you'd like me to help you with upgrading and getting a compatible modem mailed out for you, please feel free to reach out through private message.
To send a private message click on my name "ComcastChe", then click private message me. In the body of this message please verify the first and last name of the account holder, and the street address or the account number and first and last name of the account holder with your services.