Thank you so much for posting your question in the Xfintiy Forum. We sincerely apologize that you are experiencing issues with the Xfinity Stream App. We want to get this resolved for you as soon as possible, can you please reply to this thread with your answers the following questions?
What error message are you receiving when you attempt to use the Xfinity Stream app? Are you receiving this error when you are attempting to watch anything on the app or just certain programming? If only certain programming, can you please provide me what specifically you were attempting to view and how you where viewing this content (via Cloud DVR, OnDemand, live TV) when you received this error? Finally, can you tell me if this is happening when attempting to view content on your home network or while away from your home?"