{
    "error": "invalid_client_id",
    "error_description": "client identifier invalid"
}

POST /services/oauth2/token HTTP/1.1
Host: login.salesforce.com
Content-Type: application/x-www-form-urlencoded
Cache-Control: no-cache
Postman-Token: 971c9554-f8c2-99e5-1680-8a685df15d82

grant_type=password&client_id=CLIENTIDGOESHERE&client_secret=CLIENTSECRETGOESHERE&username=username@mail.com&password=MYPASSANDMYSECURITYCODE