After Installing Extra Fee, no access to config

After Installing Extra Fee, no access to config

Hi,

after Installing the Extra Fee Extention i've got this error while entering Admin -> Shop -> Configuration:

1 exception(s):
Exception #0 (Exception): Notice: Undefined index: id in /var/www/share/XXX/core/vendor/magento/module-config/Model/Config/Structure/Element/Iterator.php on line 72