Hello. We are sure that the sending address is correct and autorized. This only happens when the sender sent email to an unexistent email in our organization. All other email address from our organization in that email should receive but it dont. The error that the sender receives is one error for u...

Hello. I am using MailEnable Professional. I have an error when our costumers send email to more than one user and in the destination it's added an unexistent email, none of the emails is delivered and costumer receive 551 Sender address is not valid for your login. Check your email program settings...