error message-We could not verify your authenticated Sender Address. Please contact Customer Support

When I create and send to a list of contacts, it tells me the email will be sent, then I get an error message that states :We could not verify your authenticated Sender Address. Please contact Customer Support for more information..

This happened to me last week as well.  I called Customer Support to which I was on hold for some time before someone picked up, then they had to look at my account to see what the issue was, and I was put on hold again.  Then they came back on the phone to state there were some changes made to the account and it could take 24 hours before I could try and resend the email.

I did not get back to resending the email until today, which is 8 days later..Still got the same error message...

Please let me know what the issue is.

Thanks

Marie Smeraldo