Fatal error: Uncaught Error: Call to undefined function WP_Optimize() in /home/walid/public_html/wp-content/plugins/wp-optimize/cache/file-based-page-cache-functions.php:191 Stack trace: #0 [internal function]: wpo_cache('<!DOCTYPE html>...', 9) #1 /home/walid/public_html/wp-includes/functions.php(5107): ob_end_flush() #2 /home/walid/public_html/wp-includes/class-wp-hook.php(303): wp_ob_end_flush_all('') #3 /home/walid/public_html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array) #4 /home/walid/public_html/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #5 /home/walid/public_html/wp-includes/load.php(1097): do_action('shutdown') #6 [internal function]: shutdown_action_hook() #7 {main} thrown in /home/walid/public_html/wp-content/plugins/wp-optimize/cache/file-based-page-cache-functions.php on line 191