Error while using grant_type client_credentials

[rasikkunwar]

This is the request parameters.
{
"client_id": 3,
"client_secret": "QVmsOyziBX79dB3ryNKeq9KoRyBp14jOCh4CKYAu",
"grant_type": "client_credentials",
"scope": "*",
}

This is the error message i am getting.
"The request is missing a required parameter, includes an invalid parameter value, includes a parameter more than once, or is otherwise malformed.",