I am using 1 file. It works with product 2. It does not work with product 1. It has nothing to do with the file type. It has to do with the product that is being uploaded. The product has been corrupted somehow.
It is a standard product on a woocommerce csv file. Lets call it product 1. Product 1 does not upload but product 2 does. On the very same csv file. Its like wordpress remembers product 1 and wont allow it to upload.