filebeat now emits the following error
2021-08-17T06:00:10.472+0900 ERROR [logstash] logstash/async.go:280 Failed to publish events caused by: write tcp XXX.XXX.XXX.XXX:XXX->XXX.XXX.XXX.XXX:XXX: write: connection reset by peer 2021-08-17T06:00:12.236+0900 ERROR [publisher_pipeline_output] pipeline/output.go:180 failed to publish events: write tcp XXX.XXX.XXX.XXX:XXX->XXX.XXX.XXX.XXX:XXX: write: connection reset by peer
The logs sent from filebeat on another server are correctly received by the server running logstash.
The server on the receiving end is using iptables to accept the IP of the server in question, so I don't think it's a firewall issue either.
What other possible causes can you think of?
Any advice is welcome.