Error: Variable $apiKey of type String!

[tcouet]

Error: Variable $apiKey of type String! was provided invalid value: {"response":{"errors":[{"message":"Variable $apiKey of type String! was provided invalid value","locations":[{"line":2,"column":17}],"extensions":{"value":null,"problems":[{"path":[],"explanation":"Expected value to not be null"}]}}],"status":200,"headers":{}},"request":{"query":"\n query FindApp($apiKey: String!) {\n app(apiKey: $apiKey) {\n id\n title\n apiKey\n organizationId\n apiSecretKeys {\n secret\n }\n appType\n }\n }\n","variables":{}}}

hi, i follow readme instructions but i have this error, can you help me ? :'(