As of June 23 2020 i am now being redirect to register my modem. It was working yesturday. All of my streaming tv devices ie Amazon Firestick's are still able to stream media. However when trying to access the internet from my pc devices i keep getting redirected to register.be.xfinity.com. example below.
Try calling 1-800-comcast and ask a rep to completely remove the modem from your account and to "re-provision" it from scratch. Also ask them to confirm that the provisioning and account data in their database is correct and complete.