Elasticsearch more_like_this

Hi,
I am trying to build a search engine using more_like_this query, but the result set does not have matching documents,
In the below example i am using the text in field 4 to contain "primary" but the first document itself does not contain the text in the field, can you please check the below query and tell me where i am going wrong.

GET /indexname/typename/_search?size=10000

{
"more_like_this" : {
"fields" : ["field1", "field2", "field3", "field4"],
"like" : "primary",
"min_term_freq" : 1,
"max_query_terms" : 12
}
}