Be sure you have Java 8+ installed on the system. I installed Java 9 (assuming this fulfilled the 8+ requirement) and got the same error you are seeing. When I backed the Java version down to 8 the error went away and I was able to see the Alexa input.
... View more
I also had this, but realised i dint have java 8 installed. Once I corrected that, and restarted and it started listening.
netstat -plnt |grep 443
tcp 0 0 :::443 :::* LISTEN 27185/java
... View more