Fatal error: Uncaught Error: Interface 'Psr\SimpleCache\CacheInterface' not found in /var/www/alldocs/home/sdoehner/webtest/simplesamlphp_idp/vendor/symfony/cache/Simple/ArrayCache.php:28 Stack trace: #0 {main} thrown in /var/www/alldocs/home/sdoehner/webtest/simplesamlphp_idp/vendor/symfony/cache/Simple/ArrayCache.php on line 28