Streaming content won't play on AppleTV+ (using compatible TV)

I recently re-subscribed to Apple TV+ after a short hiatus (a couple months). I had previously been a subscriber for a few years, and never had problems accessing the channel with my Roku device and viewing on my Vizio smart TV; everything played perfectly. 

But since re-subscribing a week ago, none of the content will play on my TV.  When I try to play one, I just get a message saying:

“Unable to Play; There’s a problem playing this video. Try again or troubleshoot the issue.”

I click on “Start Troubleshooting”, and get a message saying:

“Unable to Connect; There’s a problem connecting to the Internet. Check your network connection and try again later.”

I click on “OK”, check my Wi-Fi connection, which is strong.  I receive a final message:

“Unable to Connect; There’s a problem connecting for playback. Try again later.”

I did a search in Apple Support and went through its suggestions, one of which was to try watching via the Apple TV app on my iPhone, which DID work. Beyond that, there were no other suggestions I could use.