How to Bulk update item categories

How to Bulk update item categories

I try to bulk update my items sub and main category.
For that I exported all items as xlsx file and updated the cells with the existing names.

While importing the edited xlsx file the error-message "Illegal value specified for a Dropdown field: A-1A" comes up.

What did I do wrong? i dont see a dropdown in my export file.

I haven't found a topic on this yet.

Thank you for a short guide.

Best regards
Patrick