Check the PHP/apache/iis server logs to see if there is an out of memory error. More, I found a problem on windows server which report \\ as starting path and I’m fixing it.
Thank you. In my case the problem was the ‘/’ in the path. In my windows server I need to change it to ‘\\’ in file module.php (‘newsletter/includes/module.php’), I simply do a quick fix using $file = str_replace('\\', '/', $file);