I found this thread looking for a solution to WordPress failing with 500 internal server error and in the PHP Logs:
PHP Fatal error: Class ‘Twig_Loader_Filesystem’ not found in D:\home\site\wwwroot\wp-content\plugins\gallery-by-supsystic\vendor\Rsc\Environment.php on line 171
My blog website was working for several years before this recently happened, while I was not doing any maintenance of PHP or the site.
What is the tutorial referred to by Ayron?
