Logstash runs but shows no output on server

[ste1 (Steven)]

I'm new to the Elastic Stack.

I have a logstash config which parses and filters csv files and it looks like this:

input {
    file {
        path => "/path/to/file"
        start_position => "beginning"
	sincedb_path => "/dev/null"
    }
}
filter {
  csv {
    autodetect_column_names => true
    target => "_tmp"
  }
  mutate {
    add_field => {
      "[data][email]" => "%{[_tmp][email]}"
      "[data][username]" => "%{[_tmp][username]}"
      "[data][ip]" => "%{[_tmp][ip]}"
    }
  }
  mutate {
    remove_field => ["_tmp"]
  }
  prune {
    whitelist_names => [ "data" ]
  }
}
output { // I would usually have it output to elasticsearch but for now I just have the output go to console as at first I thought the issue was in elasticsearch, but it isnt.
    stdout{}
}

After running ./logstash -f /path/to/config the config will work perfectly fine on my windows machine but not on my Ubuntu server. The only output I get is

Using bundled JDK: /usr/share/logstash/jdk
OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.

Whereas on my windows machine I get the output I expect.
There are no error logs in /var/log/logstash/

Could this be an issue with memory? My server has limited hardware.