Hi waldo99
Thanks for the info, I can access your site now.
The issue comes from the menu item type & assignment only. Let me explain a bit here.
It relates to 2 menu items: Home & Angebote & Packages. Both of these menu items have type of 'Featured Articles', this is a special menu item type in Joomla, when you show the 'News Show Pro GK5' module on homepage >> click to view an article of this module, Joomla will find the menu item that article belongs to, if the menu item 'Angebote & Packages' has another type like category blog or other type of article com_content, it will redirect to that page correctly. However, this menu item also has 'Featured articles' type - the same as homepage, so when you clicked, it will take the homepage as its menu item and kept showing on the same homepage.
I just tried to change the 'Angebote & Packages' menu item to 'Category Blog' menu type + assign category that article belongs to to this menu item and you can see it's working fine now.