How to connect Kibana to Elasticsearch when http ssl is enabled

I have disabled server.ssl settings by setting "server.ssl.enabled: false", and also # the following settins:
#server.ssl.certificate:
#server.ssl.key:

while using the CA of already existing one of elasticsearch for setting "elasticsearch.ssl.certificateAuthorities".

It runs with no error, but the browser returns


What does it mean? Does it mean that it is required to set server.ssl, i.e. step 1?