21. Instalar Laravel Passport II

Estimado Victor, queria hacerte una consulta, al momento de solicitar un token del grant_type password me sale el siguiente mensaje de error:

{
   "error": "unsupported_grant_type",
   "error_description": "The authorization grant type is not supported by the authorization server.",
   "hint": "Check that all required parameters have been provided",
   "message": "The authorization grant type is not supported by the authorization server."
}

Sera que me podrias ayudar porfavor.