ERROR IN route:cache

i got that error when i am trying command php artisan route:cache

Route cache cleared!

[LogicException] Unable to prepare route [api/user] for serialization. Uses Closure.

Iknow no closure in my Web file and thats it

#USERS ROUTES TO CONTROLLERS

Route::get('/users','UsersMngController@index'); Route::get('/users/{user}/edit','UsersMngController@edit'); Route::put('/users/{user}','UsersMngController@update'); Route::get('/users/{user}/delete','UsersMngController@destroy'); Route::get('/admins','UsersMngController@admins');

#USERS ROUTES TO CONTROLLERS

#POSTS ROUTES TO CONTROLLERS

Route::resource('posts','PostsController');

#POSTS ROUTES TO CONTROLLERS

#WELCOME PAGE

Route::get('/','HomeController@welcome');

#WELCOME PAGE

Auth::routes();

Route::get('/home', 'HomeController@index');

THX