Endpoint causes error, SSL Handshake failed

[anelima]

Hi,
I've been trying to connect my Wordpress Website to an Alexa skill for several days now via Voicewp. I followed the tutorial, however, the skill cannot be called. When testing on the Amazon Developer Portal, I get the message "The remote endpoint could not be called, or the response it returned was invalid.". When trying to call the skill using Amazon Echo, I get an answer about failing, the Alexa app tells the SSL handshake failed.

In the Amazon Developer Portal, I use the URL (via HTTPS) "https://mydomain.000webhostapp.com/wp-json/voicewp/v1/skill/news". When I open my URL in the browser, a simple text saying "To test your skill, use an Alexa enabled device or Echosim.io" is shown. There is no route error.
In the Alexa Skill Settings within the Wordpress Dashboard, the right News Skill ID is given. An SSL certificate is available.

What do I do wrong about the endpoint? Is there something important I missed when doing the tutorial?
Thank you for any answer!

[anelima]

Further research has led to an answer.

The right SSL certificate to chose is "My development endpoint is a sub-domain of a domain that has a wildcard certificate from a certificate authority". Everything works fine.