I created a very basic Alexa skill with a custom HTTPS endpoint. When invoking the skill in the demo console,Alexa says "I am unable to reach the requested skill"，The message "Unable to put through (telephone) to host" is displayed in the Alexa web app with the description "A connection could not be established to Resource [https://www.getdigital.de/echo.html?mode=request], Type [HTTP], or Region [DEFAULT]".my skillID: "amzn1.ask.skill.dcfa0f2d-e35f-4eb5-a1b1-c6"
Source: amazon.com