When I execute this code:
var_dump(file_get_contents('http://www.zahnarzt-gisler.ch'));
I get this error:
Warning: file_get_contents(http://www.zahnarzt-gisler.ch): failed to open stream: HTTP request failed! HTTP/1.1 403 Forbidden in /home/httpd/vhosts/your-click.ch/httpdocs/wp-content/themes/your-click/ajax-request.php on line 146 bool(false)
I don't know why it is returning false, since when I change the url, e.g. http://www.google.com or any other url, it will work and returns the source code of the page.
I guess it must be something wrong with the url but it just seems weird to me, because it url is online and available.