Fatal error: Uncaught Error: Call to undefined function thumbnail_generator() in /var/www/vhosts/inskola.com/httpdocs/wp-content/themes/wplms/author-course.php:72 Stack trace: #0 /var/www/vhosts/inskola.com/httpdocs/wp-includes/template-loader.php(106): include() #1 /var/www/vhosts/inskola.com/httpdocs/wp-blog-header.php(19): require_once('/var/www/vhosts...') #2 /var/www/vhosts/inskola.com/httpdocs/index.php(17): require('/var/www/vhosts...') #3 {main} thrown in /var/www/vhosts/inskola.com/httpdocs/wp-content/themes/wplms/author-course.php on line 72