php - Posting to Facebook via Website Application - Internal Server Error -

i using following code user's posts, app_id, , app_secret replaced appropriate fields.

<?php session_start(); require_once __dir__ . '/src/facebook/autoload.php';  $fb = new facebook\facebook([ 'app_id' => 'app_id', 'app_secret' => 'app_secret', 'default_graph_version' => 'v2.5',]);  $helper = $fb->getcanvashelper();  $permissions = ['user_posts']; // optionnal  try { if (isset($_session['facebook_access_token'])) { $accesstoken = $_session['facebook_access_token']; } else {     $accesstoken = $helper->getaccesstoken(); } } catch(facebook\exceptions\facebookresponseexception $e) { // when graph returns error echo 'graph returned error: ' . $e->getmessage(); exit; } catch(facebook\exceptions\facebooksdkexception $e) { // when validation fails or other local issues echo 'facebook sdk returned error: ' . $e->getmessage(); exit; }  if (isset($accesstoken)) {  if (isset($_session['facebook_access_token'])) {     $fb->setdefaultaccesstoken($_session['facebook_access_token']); } else {     $_session['facebook_access_token'] = (string) $accesstoken;      // oauth 2.0 client handler     $oauth2client = $fb->getoauth2client();      // exchanges short-lived access token long-lived 1     $longlivedaccesstoken = $oauth2client->getlonglivedaccesstoken($_session['facebook_access_token']);      $_session['facebook_access_token'] = (string) $longlivedaccesstoken;      $fb->setdefaultaccesstoken($_session['facebook_access_token']); }  // validating access token try {     $request = $fb->get('/me'); } catch(facebook\exceptions\facebookresponseexception $e) {     // when graph returns error     if ($e->getcode() == 190) {         unset($_session['facebook_access_token']);         $helper = $fb->getredirectloginhelper();         $loginurl = $helper->getloginurl('https://apps.facebook.com/app_namespace/', $permissions);         echo "<script>window.top.location.href='".$loginurl."'</script>";         exit;     } } catch(facebook\exceptions\facebooksdkexception $e) {     // when validation fails or other local issues     echo 'facebook sdk returned error: ' . $e->getmessage();     exit; }  // getting posts published user try {     $posts_request = $fb->get('/me/posts?limit=500'); } catch(facebook\exceptions\facebookresponseexception $e) {     // when graph returns error     echo 'graph returned error: ' . $e->getmessage();     exit; } catch(facebook\exceptions\facebooksdkexception $e) {     // when validation fails or other local issues     echo 'facebook sdk returned error: ' . $e->getmessage();     exit; }  $total_posts = array(); $posts_response = $posts_request->getgraphedge(); if($fb->next($posts_response)) {     $response_array = $posts_response->asarray();     $total_posts = array_merge($total_posts, $response_array);     while ($posts_response = $fb->next($posts_response)) {           $response_array = $posts_response->asarray();         $total_posts = array_merge($total_posts, $response_array);       }     print_r($total_posts); } else {     $posts_response = $posts_request->getgraphedge()->asarray();     print_r($posts_response); }  // can redirect page , use access token $_session['facebook_access_token'] } else {  $helper = $fb->getredirectloginhelper();  $loginurl = $helper->getloginurl('https://apps.facebook.com/app_namespace/', $permissions);  echo "<script>window.top.location.href='".$loginurl."'</script>"; 

}

when run locally on command line (php post.php), following:

<script>window.top.location.href='https://www.facebook.com/v2.5/dialog/oauth?client_id=843019182480437&state=bb8b088f64641baed7d1e4de734ad19b&response_type=code&sdk=php-sdk-5.1.2&redirect_uri=https%3a%2f%2fapps.facebook.com%2fapp_namespace%2f&scope=user_posts 

which means syntax correct. when go link following notification facebook:

given url not allowed application configuration: 1 or more of given urls not allowed app's settings. must match website url or canvas url, or domain must subdomain of 1 of app's domains. 

i have set website url appropriate value. when try access post.php server internal server error.

has else experienced before?