Logstash Avro data points are resulting into default value instead of the value from kafka output

[mastersmit (Smit)]

Logstash output:

{
     "timestamp" => 0,
      "username" => "",
         "tweet" => "",
      "@version" => "1",
    "@timestamp" => 2020-09-29T01:59:15.867Z
}

Kafka Consumer output:

{"username":"John Smith","tweet":"Amazing Tweet wCO00","timestamp":404000000}

tweet.avsc

{
   "type":"record",
   "name":"Tweet",
   "namespace":"com.example",
   "fields":[
      {
         "name":"username",
         "type":"string",
         "doc":"Name of the user account on Twitter.com"
      },
      {
         "name":"tweet",
         "type":"string",
         "doc":"The content of the user's Twitter message"
      },
      {
         "name":"timestamp",
         "type":"long",
         "doc":"Unix epoch time in seconds"
      }
   ],
   "doc:":"A basic schema for storing Twitter messages"
}