I am working on a service that will work with Alexa and Google Home. I am using a Lets Encrypt certificate for testing as this is accepted by Google Home. I am able to connect to my HTTPS endpoint and see that I have a perfectly valid X.509 certificate. Google Home works perfectly when testing using that endpoint.
I have heard that the Lets Encrypt certificates are not completely compatible with ASK (why?), but can be uploaded, and so I have uploaded the fullchain.pem as a self signed certificate for my skill. The uploaded fullchain.pem exactly matches the certificate delivered by my server.
Unfortunately when I try to test (English U.S. (as English U.K. does not work, but thats another forum thread) -> European server ) I get the message
"The remote endpoint could not be called, or the response it returned was invalid."
I see no incoming request on my server.
Can anybody help. The skill is called 'Volumio Control'.
Is there any way to debug this in any more detail?