This can happen under a few different conditions.
- If you select the wrong "File Seperator" for the file you are uploading.
- If you upload a .CSV and you select the wrong column for the "Email Address"
- If the column you selected for the email address has more then 20% mal-formed or blank email addresses.
If none of the above conditions apply to your file, click the "Leave a Message" button after performing a search in the HELP icon on the bottom right and supply us with a sample file to look at.