Do not try to login if user was not found

app/Providers/AppServiceProvider.php

@@ -85,10 +85,12 @@ class AppServiceProvider extends ServiceProvider
                 }
                 elseif(isset($_SERVER['REMOTE_USER']) && !empty($_SERVER['REMOTE_USER'])) {
                     $user = User::where('username', $_SERVER['REMOTE_USER'])->first();
+                    if ($user) {
                         \Auth::login($user, true);
                         session(['current_user' => $user]);
                     }
                 }
+            }
 
 
             $alt_bg = '';