Links go to joomla frontpage
This issue is because there is not any menu link to those articles and can not take the item id.
To fix this follow the steps below.
Go in Menus / about joomla (or bottom menu). There click in new.
In "Menu Item Type" click select and chose "Category Blog".
Enter any menu title example Header.
In Required Settings In "Choose a category" select the category where your articles for the header are.