GraphQL : “message”: “Unknown variable `aRTICLE_group`.”

I have the following type in my schema.graphql script:

type ARTICLE {
   _id: Long!
   community: Int!
   familyComponent: Int!
   id: Int!
   label: String!
   seed_label: Int
   title: String!
   similar: [ARTICLE] @relation(name: "SIMILAR", direction: OUT)
   keywords: [KEYWORD] @relation(name: "APPEARS_IN", direction: IN)
   group: [ARTICLE]
      statement: "MATCH (a:ARTICLE) RETURN as id, COLLECT(a) AS articles"

I tried to query it, for example:

query {

But I have the error Unknown variable aRTICLE_group

I saw that other developers have this error so I don't if the error comes from what I coded

I was having the same problem. What version of neo4j are you using?
Upgrading neo4j from v4.0.4 to v4.1.13 fixed the issue for me.