I've been running on my HE for about a month now. I have a small and simple setup. I only have four switches. Up until yesterday, I have been able to control all of them using the Alexa skill. Suddenly, for no reason, when I try to have Alexa turn on my living room switch I get 'Living room doesn't support that'. I had been working, I used it everyday. I can still control the other three switches using Alexa. Why would one switch suddenly stop working with Alexa? I'm able to turn it on/off using the Alexa app on my phone.
I've had this glitch eventually pop up with hub and bridge I have ever connected to Alexa. Sometimes it's just a matter of changing phrasing sligtly. For example, if I ask Alexa to "Turn off my front bedroom light", it will respond "Front bedroom doesn't support that". However, if I says "Alexa, turn off the front bedroom lights", it will do it. This has nothing to do with Hubitat, as that is a Hue skill. In this particular case, I believe it happens when I don't say lights, but use the singular light, because there are three lights and the Alexa skill is expecting me to specify the exact name of the light to turn off (which are front bedroom light 1, 2 and 3). Plus there is a Ecobee sensor in the front bedroom named "Front Bedroom". I could do some renaming, but I really don't want to because I want to just ask "What's the temperature in the front bedroom, and I really don't want to ask my wife to remember some odd name for the front bedroom lights that doesn't make sense to us. So I adjust my speech.
When it's not just a phrasing issue and happens too frequently, I get around it by creating an Alexa Routine with the common phrases I uses to control the device. It's ridiculous to have to use such a workaround, but it does the job. Alternatively, for devices that are not as critical, (obviously your living room light is) then I just wait a few days and it often just starts working again.
You can try rebooting the Echo. I have found that to work sometimes as well.