Mail Send Error with eNewsletter

I am getting the following error when sending an email.

Mail Send Error: SMTP Error: The following recipients failed: EMAIL-ADDRESS-IS-HERE <p>SMTP server error: </p>

I am guessing this has something to do with a bad email address? I can not figure out how to remove and restart. If I try to resend and tick the “Don’t send to people who’ve already received this” the message comes up that there are no emails to send to.

Can you suggest a solution so that I so not have to send the same email to the total list again, including those who’ve already received it?

Thanks!

-Loren