title: Laravel Passport - Grant Type Not Supported
body: <p>I have installed Laravel Passport per the documentation and I have modified all areas of my code that is required.  </p>
  
  <p>I am working on setting up Password Grant Tokens so that users will be able to get an API token when logging in with their username and password for the site.  I am hitting an issue though when it comes to the grant_type.
  For some reason Laravel is complaining about an invalid grant type.</p>
  
  <pre><code>{
    "error": "unsupported_grant_type",
    "message": "The authorization grant type is not supported by the authorization server.",
    "hint": "Check the `grant_type` parameter"
  }
  </code></pre>
  
  <p>These are the fields that I am posting to <code>/oauth/token</code></p>
  
  <pre><code>client_id = 4
  client_secret = SMiYE7XqDNtXKQnmkYmFnXxfAaV83vRhnJ9zwCtZ
  username = jcrawford@domain.com
  password = **************
  grant_type = password
  scope = *
  </code></pre>
  
  <p>I have run <code>php artisan passport:install</code> and I have also tried running <code>php artisan passport:client --password</code></p>
  
  <p>Both commands worked and both created the client and secrets, however, I cannot seem to get past the error about the grant_type.</p>
  
  <p>Any suggestions on what I should look at to get this solved so that Password Grant Tokens will work for me?</p>