While we do have a Comcast line it works through the computer and is not linked to the TV. . . and none of the features for phone notifications on the TV are activated. So I doubt that has anything to do with it.
I used to have that notification feature when I had DishNetwork in Stockton.
so was mine. my phone was over the internet and my cable was too...suggestion check a description of services provided in your phone contract you might find that the phone goes to the tv set if you don’t answer.