Warning: file_get_contents(https://gy-her.de/iserv/public/calendar?key=8051409676dd9aea320b47b366afc8c6): failed to open stream: HTTP request failed! HTTP/1.0 500 Internal Server Error in /var/www/vhosts/wordpress/public_html/wp-content/plugins/wordpress-ics-importer/ics-functions.php on line 406
Your ICS file is unable to update.