Welcome ACapps. I apologize for the inconvenience. We can look into this. We need a bit more info in order to proceed.
Are you getting the error on all of your outbound mail? If not what domains are failing, ex: email@example.com, firstname.lastname@example.org.
What mail client are you using, Outlook 2007, macmail, Barracuda, etc..? Are you getting the same error if you use port 25 and/or port 995? Did this begin with the initial setup of your Business Class email account?