Currently, I am working on Alexa smart home API (v3).I have used US(English) to develop smart home skill in Alexa developer portal.I have developed AWS lambda with us-east-1 region. I followed steps given in below link.
https://developer.amazon.com/docs/smarthome/steps-to-build-a-smart-home-skill.htmlBut, In this case lambda function is not called by Alexa when I tried to discover devices from my amazon Alexa app.
Same process is working petty great with UK(English) and AWS Lambda in eu-west-1.