Hi! I tried adding a new custom attribute for site settings (System&Settings -> Basics -> Name&Attributes -> Manage Attributes). The attribute type was 'Address', and I chose a default country for it. But something went wrong, and now it throws an error everytime I try to access /index.php/dashboard/system/basics/

The error I'm getting is:
Whoops\Exception\ErrorException thrown with message "Call to a member function getController() on null"
Stacktrace:
#0 Whoops\Exception\ErrorException in .../concrete/src/Entity/Attribute/Key/Key.php:218

Error is pointing to this function:
public function getController()
{
$controller = $this->type->getController();
$controller->setAttributeKey($this);
return $controller;
}

Concrete version 8.5.1. How can I get that error away so I can continue to add other attributes?