When I open the Xfinity Home mobile app, it presents me with a Welcome! screen, with a button "Sign In" at the bottom. I click "Sign In" and go to a browser-like screen with the address "https://login.comcast.net" at the top, and a message "This site can't be reached" (including a REALLY long Greek-to-me (sorry, Greeks!) URL quoted). I have uninstalled the app, and reinstalled it, but end up with the same result.
Galaxy S8, Android 8.0.0, Samsung Experience 9.0, additional information available on request
Hey CurlyCooper -- Thanks so much for reaching out. I was able to pull up your account and share with engineering. We believe you're seeing this because the device isn't connecting to working internet. They were able to reproduce the issue on their end and are working on including a fix which will be included in an upcoming release.