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When I try to list a Motors Item I get the following error message even though the category is a leaf category:
<LongMessage>The category selected is not a leaf category.</LongMessage>
Why am I getting this error?
When you list an Item, you need to ensure that the Category is at leaf level and also that it is not virtual.
From the response you can see that the first Category Cars (CategoryID 6051) is a virtual category and you should not try to list an item in it or any of its children, even if they are leaf level categories.