Fatal error: Uncaught Error: Call to a member function enqueue_frontend_resources() on null in /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/plugins/nextgen-gallery/src/Display/DisplayManager.php:150
Stack trace:
#0 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/plugins/nextgen-gallery/src/Display/DisplayManager.php(136): Imagely\NGG\Display\DisplayManager::enqueue_frontend_resources_for_displayed_gallery()
#1 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/plugins/nextgen-gallery/src/Display/DisplayManager.php(153): Imagely\NGG\Display\DisplayManager::enqueue_frontend_resources_for_alternate_displayed_gallery()
#2 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/plugins/nextgen-gallery/src/Display/DisplayManager.php(112): Imagely\NGG\Display\DisplayManager::enqueue_frontend_resources_for_displayed_gallery()
#3 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/plugins/nextgen-gallery/src/Display/DisplayManager.php(53): Imagely\NGG\Display\DisplayManager::enqueue_frontend_resources_for_content()
#4 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/class-wp-hook.php(324): Imagely\NGG\Display\DisplayManager->enqueue_frontend_resources()
#5 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#6 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/plugin.php(517): WP_Hook->do_action()
#7 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/script-loader.php(2262): do_action()
#8 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/class-wp-hook.php(324): wp_enqueue_scripts()
#9 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#10 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/plugin.php(517): WP_Hook->do_action()
#11 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/general-template.php(3052): do_action()
#12 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/themes/twentythirteen/header.php(19): wp_head()
#13 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/template.php(790): require_once('/homepages/19/d...')
#14 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/template.php(725): load_template()
#15 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/general-template.php(48): locate_template()
#16 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/themes/twentythirteen/page.php(14): get_header()
#17 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-includes/template-loader.php(106): include('/homepages/19/d...')
#18 /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-blog-header.php(19): require_once('/homepages/19/d...')
#19 /homepages/19/d23393752/htdocs/aufhausen-ndb/index.php(17): require('/homepages/19/d...')
#20 {main}
thrown in /homepages/19/d23393752/htdocs/aufhausen-ndb/wp-content/plugins/nextgen-gallery/src/Display/DisplayManager.php on line 150