Welcome to the RingCentral Community

I created a subscription in the sandbox with the following event filters:

/presence

/message-store

/message-store/instant?type=SMS

Here is the code for the WebHook php page in the subscription:

$v = $_SERVER['HTTP_VALIDATION_TOKEN'] || '';
  if (strlen($v)>0) {    header("Validation-Token: {$v}");  }    $json_data = file_get_contents('php://input');  $fp = fopen('[path to text file]', 'a');  fwrite($fp, "Webhook event." . " " . $json_data);  fclose($fp);  

I would expect the webhook to be called anytime an event tied to an inbound or outbound SMS occurred. Instead, nothing is happening. It is not a permissions issue with the file.

Any help would be greatly appreciated.