You are an amazing help. That did get me the same error message as channels.
I spun up a virtual Ubuntu (with GUI), and tried an install there. And...everything worked.
So I went back to the debian. So it seemed to be a URL that was blocked, I looked at the firewall but didn't see anything. So I thought maybe it was the DNS server, which was pointing to Cloudflare (1.1.1.1). I'm not sure if the DNS was blocking the stream URL...or not able to find it... so I switched it to Google (8.8.8.8).
And now....everything works. I'm not sure why 1.1.1.1 worked all this time (ever since TVE launched on channels), and now started to fail. Or...maybe that's just a red herring to a different problem, and that different problem just got fixed when I redid the DNS. All I know is it is working now.