Elastic Cloud Kibana port-forward throws 503 with default TLS enabled

Following this guidance, it seems that Kibana throws 503 error while connecting with kubectl port-forward service/quickstart-kb-http 5601

https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-quickstart.html#k8s-deploy-eck

but it started working after adding below line into /etc/hosts and accessing Kibana URL as https://quickstart-kb-http.default.kb.local:5601

127.0.0.1 quickstart-kb-http.default.kb.local

into /etc/hosts

Errors:

2019-08-19 23:57:06 +0000 [warn]: [elasticsearch] failed to flush the buffer. retry_time=33 next_retry_seconds=2019-08-19 23:57:33 +0000
chunk="590806ab8757ebe018dd5f180f845528" error_class=Faraday::SSLError error="SSL_connect returned=1 errno=0 state=error: certificate verify failed
(OpenSSL::SSL::SSLError) Unable to verify certificate. This may be an issue with the remote host or with Excon. Excon has certificates bundled, but these can be customized:\n\n Excon.defaults[:ssl_ca_path] = path_to_certs\n ENV['SSL_CERT_DIR'] = path_to_certs\n Excon.defaults[:ssl_ca_file] = path_to_file\n ENV['SSL_CERT_FILE'] = path_to_file\n Excon.defaults[:ssl_verify_callback] = callback\n (see OpenSSL::SSL::SSLContext#verify_callback)\nor:\n Excon.defaults[:ssl_verify_peer] = false (less secure).\n"

{"type":"log","@timestamp":"2019-08-20T08:40:00Z","tags":["error","task_manager"],"pid":1,"message":"Failed to poll for work: Error: Request Timeout after 30000ms"}

{"type":"response","@timestamp":"2019-08-20T08:40:07Z","tags":,"pid":1,"method":"get","statusCode":200,"req":{"url":"/login","method":"get","headers":{"host":"172.30.60.200:5601","user-agent":"kube-probe/1.13","accept-encoding":"gzip","connection":"close"},"remoteAddress":"10.176.253.77","userAgent":"10.176.253.77"},"res":{"statusCode":200,"responseTime":13,"contentLength":9},"message":"GET /login 200 13ms - 9.0B"}

{"type":"error","@timestamp":"2019-08-20T08:42:50Z","tags":["connection","client","error"],"pid":1,"level":"error","error":{"message":"139907533506432:error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert certificate unknown:../deps/openssl/openssl/ssl/record/rec_layer_s3.c:1407:SSL alert number 46\n","name":"Error","stack":"Error: 139907533506432:error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert certificate unknown:../deps/openssl/openssl/ssl/record/rec_layer_s3.c:1407:SSL alert number 46\n"},"message":"139907533506432:error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert certificate unknown:../deps/openssl/openssl/ssl/record/rec_layer_s3.c:1407:SSL alert number 46\n"}