+1
I just upgraded to Logstash 7.14.0 and am also seeing this. I have one Logstash server that performs lookups via the Logstash Elasticsearch Filter Plugin, and this plugin is now causing Logstash to crash since the upgrade from 7.13.3 to 7.14.0.
Aug 05 11:16:17 LS1 ServerName[10839]: [2021-08-05T11:16:17,173][ERROR][logstash.javapipeline ][main] Pipeline error {:pipeline_id=>"main", :exception=>#<Elasticsearch::Transport::Transport::Errors::Unauthorized: [401] >, :backtrace=>["/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/elasticsearch-transport-7.5.0/lib/elasticsearch/transport/transport/base.rb:205:in `__raise_transport_error'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/elasticsearch-transport-7.5.0/lib/elasticsearch/transport/transport/base.rb:333:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/elasticsearch-transport-7.5.0/lib/elasticsearch/transport/transport/http/manticore.rb:71:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/elasticsearch-transport-7.5.0/lib/elasticsearch/transport/client.rb:152:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/elasticsearch-api-7.5.0/lib/elasticsearch/api/actions/ping.rb:23:in `ping'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-filter-elasticsearch-3.9.3/lib/logstash/filters/elasticsearch.rb:310:in `test_connection!'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-filter-elasticsearch-3.9.3/lib/logstash/filters/elasticsearch.rb:117:in `register'", "org/logstash/config/ir/compiler/AbstractFilterDelegatorExt.java:75:in `register'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:228:in `block in register_plugins'", "org/jruby/RubyArray.java:1820:in `each'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:227:in `register_plugins'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:586:in `maybe_setup_out_plugins'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:240:in `start_workers'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:185:in `run'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:137:in `block in start'"], "pipeline.sources"=>["/etc/logstash/conf.d/redacted1.conf", "/etc/logstash/conf.d/redacted2.conf", "/etc/logstash/conf.d/redacted3.conf", "/etc/logstash/conf.d/redacted4.conf"], :thread=>"#<Thread:0x198c08c8 run>"}