Steve, you got it, thanks! Should have thought to do that. My wife turned off the 5ghz on the MTA so I could reconnect some smart bulbs after the outage, and I didn't tell her to turn it back on. Consequently, the MESH extenders apparently weren't working, which the Ubi200 relies on.
On an unrelated note, people are complaining that my voice falls out for seconds at a time. I don't notice that happening but rarely on my end. To troubleshoot, should I start a new thread?
Thanks for the solid help. I feel stupid in retrospect, though I did identify properly that I am a "basic" user, a "very basic user," haha.