Because you are submitting a large number of email addresses for validation, we need to ask you for a few more details before we can clean your file.
1. The file type must be CSV. If you manage your email list within an email service provider like MailChimp or Constant Contact, export your list as a CSV file. If your email list is in a XLS or XLSX file, follow these steps:
Open your file in Microsoft Excel
Click File, then Save As
From the Save as type dropdown menu, select CSV (Comma delimited) (*.csv)
Click Save. Your file is ready to upload.
2. The first row of your CSV file must contain column headings, and the column that contains email addresses must have the column heading Email.
3. The file must contain no more than 2 million records.