Every product in the Magento catalog can have both an ID and a SKU. The id is usually numeric while the SKU can be alphanumeric. In some installations of Magento we observed that the API will only allow SellerCloud to update based on one identifier or the other, so we added an AppSetting in SellerCloud called MagentoProductIdentifierType to control this. The accepted values are: either SKU, ID, but not both.
In some cases, Magento will give back an error message of “product not exists” until the above setting is taken care of.