All spreadsheets should be imported with emails in a single column, with only one email per row in the email column. Your file may contain other data (such as phone number, address, ect) as long as the emails are secluded to one column only - and this column contains only email data.
All files should be saved in the correct file format to ensure a successful upload to DataValidation. To export your data to an accepted file format, use the Save As or Export commands while in your spreadsheet. There are two commonly used file formats we accept:
A Microsoft Excel 97-2003 Worksheet file (.xls files)
Comma separated values text files where the comma character (,) typically separates each field of text (.csv files)
If you received the message "Formatting Error. Please view our Knowledge Base for accepted file types", you need to save your file with UTF-8 encoding and re-upload your file. UTF-16 is not currently supported.