Xfinity Comcast Activation for Apple TV apps

Just in case anyone else might run into this, Sign in to provider on the Apple TV using Xfinity Comcast accounts seems to get stuck after you use your iPhone or other iOS device to activate the first few apps. The fix for me was to go to Settings>Safari>Clear History and Website data on the iPhone and then use Safari browser again on iPhone to activate the Apple TV app using my Xfinity Comcast login. Be aware that this removes all cookies from your iOS device Safari browser so proceed with caution if you aren’t saving site passwords in your keychain or elsewhere.