Flashing Screen

I hate to bother anyone on this forum because I forgot that Roku did away with its community forum.  You might call me a cable cutter because I am an Internet only customer who streams through Roku Streaming Stick+ connected to an Impecca 32" TV.  Somewhere in Roku settings the setup deemed it equivalent to some other TV brand I do not remember.  Other than Internet connection, I do not have any regular subscriptions.  Today, while working on something entirely unrelated, a window behind my TV, my connection started to act up.  There were pauses on the news app I usually tune in.  After I backed out the screen indicated loss of connection.  I went to where Roku allows a connection check.  That's where it started flashing.  I shut off the TV.  After disconnecting everything for about 30 seconds, I checked all my connections around the TV.  My Linksys router usually flashes when it loses connection, but isn't now.  It connects into a Netgear cable modem.  After turning the TV back on, the screen flashed several times.  The screen showing connection loss flashed for seconds at a time.  Eventually it opened up to Amazon Prime, which I did not select.  While it flashed there, there was a brief error message about connection speed and resolution, too quickly for screenshots.  Eventually it settled down for me to get to my Roku Home Screen.  There was an update to apply to the Roku OS, which I just did before shutting the TV off again.  Usually some odd connection activity means an update of some kind trying to download.  I never saw anything like this.  What could the problem be?  If required, then I can describe my network more specifically.