Why i can't use String array parameter in Graphql query Android/kotlin

Question

The query is :

query profile(
   $fields: [String!]!
    ){
    fetchProfile(
       fields: $fields
     ){
       data
   }
}

and Query Variables is:

{"fields": ["Total","Safe","Eco"]}

When i try to Build , i get

Error: Variable `fields` of type `[String!]!` used in position expecting type `String!`

Footnote: I am sure that in my fetchProfile has [String!]! field. In GraphQL playground, i can get data.