Twig_Loader_Filesystem

Fatal error: Uncaught Error: Class “Twig_Loader_Filesystem” not found in /var/www/vhosts/XXX/neu.XXX/wp-content/plugins/flowfact-wp-connector/modules/valuation/core.php:255 Stack trace: #0 /var/www/vhosts/XXX/neu.XXX/wp-content/plugins/flowfact-wp-connector/modules/valuation/core.php(24): FFvaluationCore->get_html() #1 /var/www/vhosts/XXX/neu.XXX/wp-content/plugins/flowfact-wp-connector/flowfact-wp-connector.php(293): FFvaluationCore->get_overview() #2 /var/www/vhosts/XXX/neu.XXX/wp-includes/class-wp-hook.php(310): FlowfactSalesautomatConnector->get_vitual_page_detect() #3 /var/www/vhosts/XXX/neu.XXX/wp-includes/plugin.php(256): WP_Hook->apply_filters() #4 /var/www/vhosts/XXX/neu.XXX/wp-includes/class-wp-query.php(3505): apply_filters_ref_array() #5 /var/www/vhosts/XXX/neu.XXX/wp-includes/class-wp-query.php(3787): WP_Query->get_posts() #6 /var/www/vhosts/XXX/neu.XXX/wp-includes/class-wp.php(663): WP_Query->query() #7 /var/www/vhosts/XXX/neu.XXX/wp-includes/class-wp.php(783): WP->query_posts() #8 /var/www/vhosts/XXX/neu.XXX/wp-includes/functions.php(1334): WP->main() #9 /var/www/vhosts/XXX/neu.XXX/wp-blog-header.php(16): wp() #10 /var/www/vhosts/XXX/neu.XXX/index.php(17): require(‘…’) #11 {main} thrown in /var/www/vhosts/XXX/neu.XXX/wp-content/plugins/flowfact-wp-connector/modules/valuation/core.php on line 255

Ich habe wirklich keine Lust mehr auf dieses Plugin.
Hier sollte irgendwo eine Warnung stehen dass man das Plugin nicht auf Produktivseiten einsetzen sollte!
Kann mir jemand weiterhelfen?