Help with wifi.

My new Xfinity gateway is stuck in the walled garden. All traffic is being redirected with SSL certificates for susi.comcast.net and register-wg.xfinity.com, causing SSL_ERROR_BAD_CERT_DOMAIN. Phone support has reset/reprovisioned multiple times without success. I need someone to check the modem's bootfile/provisioning state and manually complete the provisioning on the backend.