GnuPG in PHP5 does not print in browser, but does it work in terminal?

I'm having a problem with PHP that I've never seen before, I'm using the GnuPG class to generate encrypted messages, but I can not use it in browser, I was wondering why, but I'm not sure, the generated variable always goes empty in the browser, but the terminal is printed perfectly.

Code:

<?php

  $text = "ISSO É UM TESTE";

  $enc = encrypt($text);

  print $enc;

  function encrypt($text){
      $gpg = new gnupg();
      $gpg->addencryptkey("KEY_AQUI");
      $enc = $gpg->encrypt("$text");
      return $enc;
  }

?>

In the browser, it simply does not work, the page is blank, in the terminal I get results, as in the image below: