This error is commonly referred as “multiple matching error” and occurs when your Product ID (UPC, EAN, JAN, ISBN, etc.) is currently associated with two or more ASINs, but the other attributes you have provided in your inventory template (title, brand, colour, size, etc.) do not match with any of these ASINs.
The provided SKU, [SKU], conflicts with the Amazon catalogue. The standard product ID value(s) provided for this SKU correspond(s) to the ASIN [ASIN]; however, some information is in conflict with the Amazon catalogue. The following are conflicting attribute value(s): Item package quantity (merchant: [merchant value] / Amazon: [Amazon value]) or part number (merchant: [merchant value]/ Amazon: [Amazon value]). If your product is this ASIN, modify these attributes to reflect Amazon catalogue values. If your product is different from this ASIN, check if the standard product ID value(s) are correct.
SKU [SKU], (ASIN [ASIN1], ([ATTRIBUTE1] merchant: [MERCHANT_VALUE] / Amazon: [AMAZON_VALUE], [ATTRIBUTE2] merchant: [MERCHANT_VALUE] / Amazon: [AMAZON_VALUE], ...)), (ASIN [ASIN2], ([ATTRIBUTE1] merchant: [MERCHANT_VALUE] / Amazon: [AMAZON_VALUE], [ATTRIBUTE2] merchant: [MERCHANT_VALUE] / Amazon: [AMAZON_VALUE], ...)), .... The product_id submitted with [SKU] corresponds to multiple ASINs [ASIN1, ASIN2, ...], but we are unable to determine which one. Please update your information to best match the appropriate ASIN. If your product is different than any ASIN, please check the product_id. If it is correct, contact Selling Partner Support for proper resolution. Feed ID: [FEEDID]. For details, see http://sellercentral.amazon.ca/gp/help/200692340
If the information in the Amazon catalogue for this product appears to be incorrect, contact Selling Partner Support.