title: Laravel 6 passport returns 400 Bad request on wrong credential
body: <p>I use Laravel 6 passport <strong>grant password</strong> for my Vue backend.</p>
  
  <p>When i send right credential to <strong>oauth/token</strong> it works and returns token, but when i send wrong (email/password) it returns 400 instead of 401 with this message.</p>
  
  <pre><code>    {
      "error": "invalid_grant",
      "error_description": "The provided authorization grant (e.g., authorization code, resource owner credentials) or refresh token is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.",
      "hint": "",
      "message": "The provided authorization grant (e.g., authorization code, resource owner credentials) or refresh token is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client."
  }
  </code></pre>
  
  <p>I checked <strong>client_id</strong> and <strong>client_secret</strong>.</p>
  
  <p>I tested with new installed <strong>Laravel</strong> + <strong>passport</strong> with out single line of code, Laravel 5.8 returns 401 without any problem but Laravel 6 returns 400 bad request. </p>
  
  <p>Do you have any Idea? </p>