This problem has been complained about since 2012 and it still hasn't been fixed. (Look it up). I'm getting the message: "There was a problem loading the grid, reload your browser." --NOT the problem, NOT the fix, and Xfinity knows it!
Other fixes that don't work: changing locations, changing browsers, changing whole computer systems.... Yeah, we can get our listinings elsewhere, but Comcast, can't you show a little professionalism on your own website?
