If Alexa is unable to process your request, you may need to re-do the skill for the simple thermostat.
How to Disable and Re-enable amazon Skill
- Log in to your Amazon Alexa App or Alexa portal at Alexa.amazon.com
- Click on "Skills"
- Click on "Your Skills" on the top left
- Click "Simple Thermostat" Skill
- Click "Disable Skill"
- Click "Enable Skill"
- Alexa App or portal will tell you to discover devices.
This should resolve any issues you had.