App error TVAPP-00287 on Roku

I haven't been able to find ANY reference online to this app error. You would think Xfinity would have it in their list or search. Yes, it's TVAPP-00287 .

As with many other error codes, it says "Video cannot be played." This started happening off and on a few months ago. I noticed that the app updated on a few devices from the black icon with white letters to a purple icon. I figured they must have fixed the problem with an update as it's working with the update on at least one tv.  However, it completely stopped working on another (different brand) once you try to select anything whether from the guide or Saved and such. It buffers for a long time then gives this message here and video error. It's ALWAYS  TV-APP-00287. 

Then, it wouldn't work on a Roku Ultra attached to a different tv. This one had been having problems off and on also.

I went so far as to not just restart the Hisense Roku tv but also remove the app then restart. After relinking the account, the problem is still the same. I am considering Factory Reset on the Hisense Roku TV.  HOWEVER, since removing/installing the app affects all Roku devices, it reinstalled on the Roku Ultra attached to a different tv.  That one has the same problem now. I DID factory reset the Ultra, reinstalled the app as happens once the account is linked, and tried again. THE SAME ERROR appears when I actually try to watch something on the Xfinity app.  It is now USELESS for Xfinity.   I don't know how it has continued to work on yet another device (TCL Roku tv) that streams through the app. It sometimes has the problem. Typically, a restart fixes it as it mostly did on the other devices prior to the app update.

I have another Ultra device I'm reluctant to turn on and try as well as an already slow Roku streamer.

NOTE: the Roku tv and Ultra device do work with every other app. Streaming on those isn't a problem, and my wifi connection is Excellent.

CAN ANYONE HELP ME?  I have no use for Xfinity tv if this is their modus operandi.