You can enter up to 200 email addresses at once. You have the option of doing this manually or using a Text file to copy and paste the email addresses into the Customer Center.
Important: If you are copying from an Excel file, it’s recommended that you paste into a text editor (e.g. Notepad, TextEdit) then copy and paste into the Customer Center from there. Copying and pasting directly from an Excel file to the Customer Center is not recommended.
Additionally, make sure there is only one email address per line and no spaces before or after the email address or else the test will not send.