In similar post year, but no real resolution. I’ve had this thermostat for two years, almost 3, only recently has it started to drop Wi-Fi, usually after a day or two. I reset the thermostat network, I reset, my modem, I reconnect, it works for a day, and then it goes off-line again. The original batteries had a voltage of 3.0 something, so I replaced them with new batteries, the voltage is 3.2. It does have a C wire, and this is the first time I’ve had trouble with it in almost 3 years, any advice?
Sorry to hear about the trouble. I wanted to follow up and see if I could be of any help. I found an article with some troubleshooting steps for when the device is showing offline. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.