There are several reasons you received this error:
- You chose a vendor template but the data you are trying to import does not match the template
- The file you are trying to import has no extension (like .csv, .txt, .xlsx)
- You are trying to import an Excel file but the file is not an Excel file!
- The Excel file is a .xls file instead of a .xlsx file. To change the extension, open it in Excel, go to "Save As" then choose .xlsx. Then reimport the file.
- The Excel workbook has more than one sheet in it. Delete any extra sheets (or move them to a new workbook) and import a single spreadsheet at a time.
- The Excel file has too many items. Sometimes a vendor sends you their entire catalog of 30,000 items. You don't want that! You just want the items you order.
Here are links to some order guide file layouts and templates in case you need them.