Sending duplicate e-mails

[elwell1 verizon net]

Using, balsa, I have started sending multiple copies of e-mails. One e-mail account doesn't mind & passes the duplicates right through to the recipients, but my verizon account generates what balsa identifies as a submission problem, except every week or so, when it decides to let the messages through.

I am sure this is not balsa's fault, but I need some help in figuring out how to fix it (Verizon only does Windows). Can anyone advise me on where to look and what to look for to see what is happening between the time I hit "send" and my system sends 2 or 3 copies?

David Elwell