Can I have a recipient more than once in a campaign source files / spreadsheets?
Yes, you will receive a warning if you try uploading a source file where the same recipient appears more than once, but you can choose to ignore and send the campaign anyway. The recipient will receive multiple emails from you (depending on the number of times they appear in the spreadsheet). This feature can be useful if you need to send different email contents to the same recipient.
You can have the same recipient in a single spreadsheet up to 50 times.