Thanks for reaching out. Have you tried to cast from other apps aside from YouTube and Xfinity? What mobile phone are you using? Please try the steps listed below:
Let me know how it goes.
Just checking in to make sure that you've seen our response. Please let us know if you have other questions or concerns as we will be locking this in 24 hours if we won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
Thanks for the help, Jeran.