You must check for new mail before you can send mail on our system. This ensures that only authenticated users can send email, which prevents the sending of spam through our servers.
Checking for new email
If you get the following error message when you try to send email, "Relaying denied: You must check for new mail before sending mail," you should check for new mail before you attempt to send again. Email clients differ, but in most cases you should move the sent items from your "Outbox" to another folder, click the “Send/Receive” button, wait for any new messages to appear in your “Inbox” and send your email again.
Composing email offline
You may receive the same error message because you have composed email offline. If you put the email in your “Outbox” before you go online, some email clients will try to send the message before checking for new ones. This will cause an error. To compose email offline without an error, save the email in a place other than the “Outbox.” Check your account for new email when you go online, and then send the email after you have checked your account for new mail.