I'm guessing that you're using aol.com as your email account provider.
According to information other IncrediMail users have sent, we were able to check into the matter and found that AOL changed settings within their server, affecting our AOL IncrediMail users. AOL has confirmed this change, and we are both investigating the issue, in order to find an immediate solution.
If you would like further information, you should contact AOL Support.
Again, thank you for your assistance, and dedication in helping to keep IncrediMail running smoothly!
IncrediMail Customer Support