Stream App not streaming on Roku TV

My Westinghouse Roku TV has stopped streaming via the Xfinity stream app. I can load the app fine, but after selecting the show I want to see, it just spins and spins, telling me it is trying to reconnect. I know it is NOT the tv because all of the other apps stream fine. It is also not my Xfinity account, because I had to re-enter it after I reinstalled the app. 

I have done all of the recommended fixes (delete and reinstall app, unplug tv, etc.) but nothing works. I DO NOT get any error messages. 

It was working fine until about a week ago, when all of my Comcast products just stopped working. Internet, tv, phone - everything went out for about 3-4 minutes. Since then, the stream app has not worked at all. And the signal strength has been very shoddy. My hard-wired cable tv is glitching constantly on certain channels. The digital signal is quite weak, it appears. 

Might this have to something to do with the inability of the stream app to actually stream? 

I have read many of the other posts about this same issue from the past few years, but, as usual, Comcast does not seem to want to provide any solutions. 

Hopefully this time will be different. 

And, since many people have had, and are having, this same issue, you do not really need to ask for a direct message from me to bring up my account. Please just post a logical, step-by-step solution to the problem that EVERYONE who comes across can use to fix their stream app. After all, that is why you are here. 

Thank you.