Logstash doesn't send logs to elastic (Windows)

Question

I have a Spring boot application, that produces logs into a file. I also have running Elastic search (in docker) and Kibana and Logstash (not in docker).

This is my Logstash config:

input {
  file {
    type => "java"
    path => "C:\Users\user\Documents\logs\semblogs.log"
    start_position => "beginning"
  }
}

output {
  elasticsearch {
    hosts => ["localhost:9200"]
  }
  stdout {
    codec => rubydebug
  }
}

Elastic is up and running. When I check for the data in index that was created like this:

http://localhost:9200/logstash-2019.11.04-000001/_search

it shows:

took    0
timed_out   false
_shards 
total   1
successful  1
skipped 0
failed  0
hits    
total   
value   0
relation    "eq"
max_score   null
hits    []

In Kibana I also can't create an index, it says there are no data in elastic.

I suspect that Logstash is not sending incoming anything to Elastic, but I don't know why. There ARE logs in the log file from the app...