Thanks yvesracine and erickv for the quick replies.
Yves, I didn’t post to the My Ecobee thread since it seemed (to me) like it might be a problem on the Ecobee side so wanted to see if anyone else saw a problem. I’m not sure when I last updated the My Ecobee items, but it was during 2019 that my ST hub died and to replace it with the v3 hub required setting everything up again.
I did go through the Ecobee init on the ST app again last night and reauthorized with Ecobee. As of this morning, I see that the Ecobees are both responding again and have since about midnight (that could have been around when I re-did the Ecobee authorization or it could have just recovered on its own?).
So not sure if it was related to erickv’s “Issues with Device Control” or a need to re-authorize with Ecobee. I hadn’t changed the password or credentials with Ecobee recently, so it shouldn’t have needed a reset.
Bottom line, after being unable to communicate for a couple of days, it has been working since late last night. I’ll keep an eye on it and see if it happens again.
P.S. to yvesracine, Yes, the My Ecobee has been extremely reliable for us and it was what “signalled” to us that the connection wasn’t working. We have a routine set up with Amazon Echo that when we tell it “goodnight”, it automatically sets ST hello mode to “Sleeping” (which it does regardless at midnight). The switch to that mode turns off all the relevant lights, makes sure the locks are locked, and uses your ecobeeChangeMode smartapp to set the Ecobee to “night” mode which sets back the temp. When the furnace didn’t turn off (which it usually does shortly after we say “goodnight”), it caused the investigation. Overall, I’m really happy with how My Ecobee works and the flexibility it adds to the Ecobee integration!