Please help

Prime works.  Netflix works.  Roku and Hulu work.  Xfinity Stream does not work.  It fails 5 out of 7 days per week minimum.  Xfinity chat bot doesn't help

Xfinity "live" chat doesn't help. I updated the router ($$$). I installed a net ($$$).  This is not a connection issue or something in my network or ALL of the other services would be affected as well. They are not.  

NEED HELP! PLEASE!  FINALLY!  FOR [Edited: "Language"] SAKE.