Q: eBay LMS Trading API AddFixedPriceItemRequest returns 'SKU already in use' error I've been working on an automatized eBay-upload-item module for a while now and every time I think it could work, eBay comes up with a new non-sense error. Currently the error is: 
SKU already in use

I have 0 items in my listing, (active, ended, unsold etc), literally, 0 items anywhere. And when i try to make a BULK upload via the Trading API using individual AddFixedPriceItemRequest per item (including variations), I get the above error, which makes no sense. 
All my SKUs are uniquely generated and then checked for against a database that stores them so as to avoid duplication. There is no documentation anywhere, and just basing my debugging on eBay's error reporting can drive anyone into insanity. 
Any help will be much appreciated. Thanks

A: First of all, make sure that the item you're trying to upload is not a Multi-SKU item. This error can appear for multiple problems related to any part of your listing. 
It would be also great if you can post API request and response here.
