Error using POST with users/lookup and Twitter-API-PHP library


I’m trying to use the method users/lookup with a POST request and the Twitter-API-PHP library. Here is my code:
$url = ‘’;
$postfields = array(
‘user_id’ => ‘23687576,358392502’
$requestMethod = ‘POST’;
$twitter->buildOauth($url, $requestMethod);
$result = $twitter->performRequest();
$result2 = json_decode($result);
return $result2;

I get this result: public ‘message’ => string ‘Sorry, that page does not exist’ (length=31). However, If I use the GET method with the same IDs I get the expected result.

What am I doing wrong?

Thanks in advance.


By the way, other POST requests work correctly.