IIf with DMax in a query not working

Hello All,

I normally find answers reading forums but this time I am stuck. Now begging for help :o

I attached a screenshot of my latest attempt (tried a couple of things, never good...).

With it I receive the following error:

"The specified field '[Category]' could refer to more than one table listed in the FROM clause of your SQL statement."

I understand there is an issue with "Category", but I don't know how to resolve the case.

Thanks for some advises,

pit

Attached Images

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