My wife and I have had the same problem for about 10 days, first with our iPhone 5's while in Arizona and now continuing in Colorado as of last night with our iPhone 6's. I hgave not found any on-line fixes that really work. The guys at the Apple store had us delete the original account and then set up our Comcast accounts again. The worked for a few hours and then stopped again. When they had my wife try to set up her account using a floated phone in the store (Apple 4 or 5) the same thing occurred. Their conclusion, which I believe to be correct, is this is a Comcast problem (no surprise there!) not an Apple iPhone problem.
My wife and I have had the same problem for about 10 days, first with our iPhone 5's while in Arizona and now continuing in Colorado as of last night with our iPhone 6's. I hgave not found any on-line fixes that really work. The guys at the Apple store had us delete the original account and then set up our Comcast accounts again. The worked for a few hours and then stopped again. When they had my wife try to set up her account using a floated phone in the store (Apple 4 or 5) the same thing occurred. Their conclusion, which I believe to be correct, is this is a Comcast problem (no surprise there!) not an Apple iPhone problem.