In this case, you have tried to upload a file with a duplicate SKU.
- Use CTRL + F in your Excel sheet to lookup the SKU's listed.
- Single buyer: Make sure the SKU is unique in your file. Multi buyer: Make sure that per SKU (for all different buyers) all the information is the same. Except for the price, the price can be different per Buyer.
- You can delete the duplicate products or change one of the SKU's if its multiple separate products.
- You can find duplicates in your sheet with the function under 'Conditional Formatting > Highlight Cells Rules > Duplicate Values'.
- Make sure you select the column SKU, and the duplicate values will be highlighted.