GraphQL - Mutation

I’m having trouble running the script below for a GraphQL:

Script

    ${nome_testExectution}  Set variable       Automatic Execution

    ${GraphQL}  Format String    ${EXECDIR}\\Docs\\Templates\\CreateTestExecution.json
                  ...     nome_testExecution=${nome_testExectution}             
                  ...     id_projeto=${id_projeto}

    &{headers_import}   Create Dictionary   Authorization=Bearer ${token}         
                                ...     Content-type=application/graphql

    ${RESPONSE}    Post Request            alias=api_xray  uri=${API.GRAPHQL}    
                         ...     data=${GraphQL}     headers=${headers_import}

${RESPONSE.json()} => {'errors': [{'message': 'Must provide query string.'}]}

CreateTestExecution.json

mutation {{ 
    createTestExecution(
        jira: {{
            fields: {{ summary: "{nome_testExecution}", 
                      project: {{id: 123456}}
                    }}
              }}
                       ) 
    {{testExecution {{
                   issueId
                   jira(fields: ["key"])
                    }}
        warnings
        createdTestEnvironments
    }}
}}

I performed this mutation on Postman and it works.
Could you help me understand why this error returns?
Thanks