title: Laravel Passport TokenGuard::__construct() must implement interface
body: <p>I'm creating a rest api with Laravel and Laravel Passport. I try to access a route protected with the default laravel api auth middleware:</p>
  
  <pre><code>Route::middleware('auth:api')-&gt;get('/user', function (Request $request) {
      return $request-&gt;user();
  });
  
  Route::prefix('auth')-&gt;group(function () {
      Route::post('login', 'Auth\ApiAuthController@login');
  });
  </code></pre>
  
  <p>In the request header I pass <code>Authorization: Bearer &lt;my_secret_token&gt;</code> but I get this exception:</p>
  
  <pre><code>Argument 1 passed to Illuminate\Auth\TokenGuard::__construct() must implement interface Illuminate\Contracts\Auth\UserProvider, null given, called in /Users/markusheinemann/Projekte/Lycus/application/vendor/laravel/framework/src/Illuminate/Auth/AuthManager.php on line 162
  </code></pre>
  
  <p>Here my request header:</p>
  
  <pre><code>{
    content-type: "application/json",
    x-requested-with: "XMLHttpRequest",
    authorization: "********",
    user-agent: "PostmanRuntime/7.13.0",
    accept: "*/*",
    cache-control: "no-cache",
    postman-token: "ebfa3211-958d-4042-ab6a-a488847fc2f7",
    host: "localhost",
    accept-encoding: "gzip, deflate",
    connection: "keep-alive"
  }
  </code></pre>
  
  <p>Here my token creating process:</p>
  
  <pre><code>public function login(LoginRequest $request)
  {
      $credentials = $request-&gt;only(['email', 'password']);
  
      if(!Auth::attempt($credentials)) {
          return response()-&gt;json(['message' =&gt; trans('auth.failed')], 401);
      }
  
      $token = $request-&gt;user()-&gt;createToken('Lycus Frontend Client');
      $token-&gt;token-&gt;save();
  
      return response()-&gt;json([
          'accessToken' =&gt; $token-&gt;accessToken,
          'expiresAt' =&gt; $token-&gt;token-&gt;expires_at,
      ]);
  }
  </code></pre>
  
  <p>Has anyone an idea why I get this error?</p>