Adding new fields from grok filter in logstash

[userASR (ASR)]

I have a grok filter in my logstash conf. Where I match a message and I want to add a new field "newfield" and populate value from one specific field "data1" from the message. Here is how my configuration looks like:

input {
  file {
    path => "/var/log/myapp/myapp.log"
    sincedb_path => "/var/log/logstash/.sincedb2/myapp.log"
    start_position => beginning
    type => "myapp"
  }
}
filter {
   grok {
        match => {
          "message" => "%{TIMESTAMP_ISO8601:timestamp}\s+%{LOGLEVEL:loglevel}\s+%{JAVACLASS:class}:\s+%{WORD:word1}\s+%{WORD:word2}:\s+%{WORD:word3}=%{DATA:data1}+%{GREEDYDATA:content}"
       }
    }
    mutate {
        add_field => [ "newfield", "%{data1}" ]
    }
   if ("grokparsefailure" in [tags]) { drop {} }
}
output {
  if [type] == "myapp"{
    elasticsearch {
      hosts => [{% for node in elastic_data_hosts %}"{{node}}:{{elastic_port}}"{% if not loop.last %},{% endif %}{% endfor %}]
      index => "logstash-myapp-log"
     }
  }
}

I can see the new field added on Kibana but the value is not getting assigned. Am I doing it wrong or missed anything?