Serialization error: Unknown magic byte!

[retgoat]

Hello!
Guys, I have an error with Serialization of data.
Message serialized successfully pushed to kafka. But on the other side of Kafka another application reads the Kafka queue and deserializes my message.
But deserializarion causes an exception:

greenRiver[ERROR] Processing geronimo_entities offset 20
greenRiver[ERROR] message: Objavro.codenullavro.schema{"type":"record","name":"entities","fields":[{"name":"content","type":["string","null"]},{"name":"content_type_id","type":["int","null"]},{"name":"created_by","type":["int","null"]},{"name":"id","type":["int","null"]},{"name":"inserted_at","type":["string","null"]},{"name":"kind","type":["string","null"]},{"name":"schema_version","type":["string","null"]},{"name":"scope","type":["string","null"]},{"name":"storefront","type":["string","null"]},{"name":"updated_at","type":["string","null"]}],"namespace":"com.foxcommerce.geronimo"}���*k|^��Y_�5�x��{"title":"Some title foooooo","tags":["tag","another"],"body":"Lorem ipsum","author":"John Doe" ,2017-06-28T09:27:51.0ZBlogPost,2017-06-28T06:31:54.0Z1foo.bar,2017-06-28T09:27:51.0Z���*k|^��Y_�5�x
greenRiver[ERROR] Error deserializing avro message with key entities_16: error org.apache.kafka.common.errors.SerializationException: Error deserializing Avro message for id -1
greenRiver[ERROR] 	Objavro.codenullavro.schema{"type":"record","name":"entities","fields":[{"name":"content","type":["string","null"]},{"name":"content_type_id","type":["int","null"]},{"name":"created_by","type":["int","null"]},{"name":"id","type":["int","null"]},{"name":"inserted_at","type":["string","null"]},{"name":"kind","type":["string","null"]},{"name":"schema_version","type":["string","null"]},{"name":"scope","type":["string","null"]},{"name":"storefront","type":["string","null"]},{"name":"updated_at","type":["string","null"]}],"namespace":"com.foxcommerce.geronimo"}���*k|^��Y_�5�x��{"title":"Some title foooooo","tags":["tag","another"],"body":"Lorem ipsum","author":"John Doe" ,2017-06-28T09:27:51.0ZBlogPost,2017-06-28T06:31:54.0Z1foo.bar,2017-06-28T09:27:51.0Z���*k|^��Y_�5�x
greenRiver[ERROR] Not processed: geronimo_entities offset: 20
greenRiver[ERROR] Failure during processing geronimo_entities offset 20: org.apache.kafka.common.errors.SerializationException: Error deserializing Avro message for id -1
greenRiver[ERROR] org.apache.kafka.common.errors.SerializationException: Error deserializing Avro message for id -1
greenRiver[ERROR] Caused by: org.apache.kafka.common.errors.SerializationException: Unknown magic byte!

Here is the schema

%{fields: [%{"name" => "content", "type" => ["string", "null"]},
   %{"name" => "content_type_id", "type" => ["int", "null"]},
   %{"name" => "created_by", "type" => ["int", "null"]},
   %{"name" => "id", "type" => ["int", "null"]},
   %{"name" => "inserted_at", "type" => ["string", "null"]},
   %{"name" => "kind", "type" => ["string", "null"]},
   %{"name" => "schema_version", "type" => ["string", "null"]},
   %{"name" => "scope", "type" => ["string", "null"]},
   %{"name" => "storefront", "type" => ["string", "null"]},
   %{"name" => "updated_at", "type" => ["string", "null"]}], name: "entities",
  namespace: "com.foxcommerce.geronimo", type: "record"}

Here is the message

%{"content" => "{\"title\":\"Some title foooooo\",\"tags\":[\"tag\",\"another\"],\"body\":\"Lorem ipsum\",\"author\":\"John Doe\"}",
  "content_type_id" => 1, "created_by" => 4, "id" => 16,
  "inserted_at" => "2017-06-28T09:27:51.0Z", "kind" => "BlogPost",
  "schema_version" => "2017-06-28T06:31:54.0Z", "scope" => "1",
  "storefront" => "foo.bar", "updated_at" => "2017-06-28T09:27:51.0Z"}```

Here is the encoded message

{:ok,
 <<79, 98, 106, 1, 3, 232, 8, 20, 97, 118, 114, 111, 46, 99, 111, 100, 101, 99,
   8, 110, 117, 108, 108, 22, 97, 118, 114, 111, 46, 115, 99, 104, 101, 109, 97,
   172, 8, 123, 34, 116, 121, 112, 101, 34, 58, 34, 114, 101, 99, ...>>}

We're using confluent platform

Any advices?

Many thanks!

[retgoat]

It seems encoded message prepended with schema. This is the issue.
The message should be encoded as follows: http://docs.confluent.io/3.1.0/schema-registry/docs/serializer-formatter.html#wire-format