Hi @phlepper,
Please post under My Ecobee thread to avoid creating different topics in the ST community forum.
To answer your question:it could be a problem on the ST side (ex. connection pools to the Ecobee APIs or a shard related problem) or it could be some specific APIs issues on the Ecobee side… You won’t be able to get a definitive answer on this…
It’s not the code per se as you have had a pretty good run for the last 3 years with My Ecobee device which proves it’s resilience!
Please follow the instructions indicated under my thread.
If you haven’t updated the code since 2017, please take some time to do so, and reinstall the devices. In your case, you’d need to create new devices, and reselect the new devices in all your smartapps & routines in order to delete the old devices after.
It’s a bit more tedious update than usual as MyEcobeeInit (Service Manager) since V4 now handles a different kind of tokens (jwt)
P.S. The online or offline status doesn’t mean much for a cloud-to-cloud integration, you’d need to check the events history to make sure that you still get refresh temp/setpoint/revision values from the Ecobee APIs. Please deactivate the Device Health check as it sometimes causes more offline issues with devices.
Regards.