So, first let me start by saying that this worked fine for about a year. I got the Honeywell T-series WiFi Thermostat, and also a Honeywell Lyric C2 Camera, and had them both successfully integrated with Alexa as soon as I got them last summer (2018). I have been using Alexa to control both the Thermostat, and the Camera (viewing the output on the camera on my Echo Show device) the whole time, no issues.
A couple months ago, I started asking Alexa what the temperature was on the thermostat - something I'd done many times before - and she started saying that my device doesn't appear to support that yet. News to me since it has been supporting that for a year!
So, I went through all the usual steps - disabled the device, disabled the skill, reinstalled the Honeywell App on my phone and reconfigured it there, verified the Honeywell Home app can see the thermostat and control it, verified that the WiFi on the thermostat is connected, and so on.
So when I go to enable the Honeywell Home skill again in Alexa, it asks me to link my account again, and then I go to Discover Devices and it never discovers the Camera or Thermostat. I'm more concerned about the thermostat at this point but it seems like something just isn't working between Alexa and Honeywell anymore.
did you change the way you asked for the temperature? I have an honeywell thermostat too but it is the cheap one that was released before alexa was born. sometimes when I asked for the temperature it too says not supported but it usually fixes itself. I usually say, "alexa, what is the temperature in here."
That is the exact phrase I have always used - "Alexa, what is the temperature in here?" And all of a sudden, her response is always "It doesn't look like your device supports that yet." I did not change anything at all.
Also - as mentioned, I deleted the devices from Alexa, and now she can't even discover them, so she doesn't even know I have a thermostat.