If you SSN is four numeric digits, you may still get an error if it starts with a zero. To correct the error:
- Highlight the entire spreadsheet (Ctrl + A).
- Right click anywhere on the spreadsheet.
- Select Format Cells.
- Under the Number tab, make sure the Category is set to 'Text'.
- Click 'OK'.
- Delete the value in the first cell of data under SSN (this is row #2 in Excel).
- Re-enter the value in the first cell.
Save the spreadsheet and upload again. If the problem persists, repeat steps 6 and 7 for any SSN cells that are listed in the error messages.