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When trying to add product information during add, revise or relist, I often get this error
<ShortMessage>Invalid product identifier.</ShortMessage>
Here is a product that I had trouble with -
<LongMessage>The value <83703845> of type <ProductReferenceID> does not exist in our Catalog.</LongMessage>
The product appears to be in your catalog - http://catalog.ebay.com/83703845
Why, then, is it giving this error?
You are right the product does exist in the catalog and you should be able to add this information during revise/relist or even when creating a new listing.
Error during listing -
The reason you are getting this error is because the request specifies a categoryID that does not match the category associated with the product. Please note that when listing against catalog products, categoryID is optional. If the product finds a match in our catalog, we will list the item in the appropriate category.
Therefore our recommendation would be to not include the PrimaryCategory container in your listing request.
Error during revse/relist -
The reason you are getting this error is because the item is listed under a category that does not match the category associated with the product.
When you list an item using product information, you do not need to specify the CategoryID in the request. eBay lists the item in the category associated with the product. However, during revise or relist if the item is listed in a category that does not match the category associated with the product, the call fails because the item's category takes precedence.
In order to get past the error, find the categoryID associated with the product. In the case of this product it is - 51291 i.e. Computers & Networking > Printer Parts, Supplies & Accs > Ink Cartridges > Branded > Single Units.
Now in your revise/relist request, pass in the CategoryID associated with the product and the call will go through. See XML snippet below for sample -