Logstash can not connect Elasticsearch URL

Hello Team,
When I run the following command:
./logstash -f logstash-conf-name (from /opt/logstash/bin directory)
I get the error as follows:
[2020-09-23T22:08:16,324][INFO ][logstash.runner ] Starting Logstash {"logstash.version"=>"6.8.6"}
[2020-09-23T22:08:18,023][ERROR][logstash.licensechecker.licensereader] Unable to retrieve license information from license server {:message=>"Host name 'ABC.dmz.lava' does not match the certificate subject provided by the peer (CN=ABC.dmz.lava, OU=171855, OU=CATE, O=Xyz group Inc., C=US)"}
[2020-09-23T22:08:18,067][ERROR][logstash.monitoring.internalpipelinesource] Failed to fetch X-Pack information from Elasticsearch. This is likely due to failure to reach a live Elasticsearch

[WARN ] 2021-06-30 07:10:31.160 [Ruby-0-Thread-4: :1] elasticsearch - Attempted to resurrect connection to dead ES instance, but got an error. {:url=>"https://XXXXXXX:9200/", :error_type=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError, :error=>"Elasticsearch Unreachable: [https://XXXXXX:9200/][Manticore::ClientProtocolException] Received fatal alert: handshake_failure"}

What file changes do I need to make in order for logstash to recognize elasticsearch?

I would appreciate any advice or hints, thank you!

What version of Elasticsearch are you using?

Version: 6.8.6, Build: default/tar/3d9f765/2019-12-13T17:11:52.013738Z, JVM: 1.8.0_251