Hello, I started using MailMerge Pro to mail my Newsletter to a list of 1500. I'm sending it in SMTP, w/BCC. Members said they were getting multiple emails of the letter, a few unsubscribed. I only got one in our box. Next time I put in my off site email address and and sent a another newsletter. I recieved 22 newsletters. I'm afraid everyone recieved this many. I've gone through everything, but I can't experiment with my subscribers. Can anyone help?

What causes multiple mailings to go out?