If you are receiving the "Product can't be blank" error on your error file, check to see what file variation Gateway is recognizing your upload as. If you upload a bulk file (third-party catalog), but the file variation is recognized as a Price and Quantity file instead, that indicates that there is something wrong with the file type itself.

Please make sure that you are saving your file as the correct .csv type and re-upload; see below. Note, when re-saving your file, make sure that your UPCs are saved as text and not saved over in scientific notation.