跟教程使用laravel-wechat，token验证成功，可是发送消息时，提示“该公众号暂时无法提供服务，请稍后再试”

麻烦诸位了，帮忙看看是什么问题。我是新手，折腾好久了，还是无法解决问题。

路由文件

Route::get('/', function () {
    return view('welcome');
});

Route::group(['middleware' => ['web']], function () {
    // 不要放这里就不会启用 csrf});

Route::any('/wechat', 'WechatController@serve');<br></br>

控制器文件

class WechatController extends Controller
{
    public function serve()
    {
        Log::info('request arrived.'); 
        $wechat = app('wechat');
        $wechat->server->setMessageHandler(function($message){
            return "欢迎关注 overtrue！";
        });

        Log::info('return response.');

        return $wechat->server->serve();
    }
}<br></br>

laravel日志

[2016-04-07 17:49:27] local.ERROR: exception 'Illuminate\Session\TokenMismatchException' in /var/www/wechat_riguo/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php:67
Stack trace:
#0 [internal function]: Illuminate\Foundation\Http\Middleware\VerifyCsrfToken->handle(Object(Illuminate\Http\Request), Object(Closure))
#1 /var/www/wechat_riguo/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#2 [internal function]: Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
.......后面还有好长......

WeChat日志

[2016-04-07 17:59:40] easywechat.DEBUG: Current configuration: {"debug":true,"use_laravel_cache":true,"app_id":"wxa286a68def0e2c","secret":"8cbb4a67c5b3d50844d6252ccb1817","token":"wechat","aes_key":"OAdbkQMMv7i6wytvBQbsCWCAvlhf6kiofG6R1i9DpCE","log":{"level":"debug","file":"/var/www/wechat_riguo/storage/logs/wechat.log"  []
[2016-04-07 17:59:40] easywechat.DEBUG: Request received: {"Method":"GET","URI":"/wechat?signature=bdf0cd824e1d0ef663f9d093308480e6565e0f62&echostr=3427265654774280636&timestamp=1460051980&nonce=413835758","Query":"echostr=3427265654774280636&nonce=413835758&signature=bdf0cd824e1d0ef663f9d093308480e6565e0f62&timestamp=1460051980","Protocal":"HTTP/1.0","Content":""} []
[2016-04-07 17:59:40] easywechat.DEBUG: Output 'echostr' is '3427265654774280636'. [] []<br></br>