Sender Verification Failure

If you were told to look at this web page, your email to us was rejected because we couldn't verify the sender's (your) email address. This can happen for many different reasons, but often it's due to an SMTP server configured to refuse bounce messages. If this doesn't mean anything to you, you might want to have your email administrator look at this web page.

The SMTP server which most commonly has this problem is Imail. Imail is a mail server for Windows NT, 2000 and XP which is often configured to refuse "bounce" messages. These are email messages that other systems send when email is undeliverable. For example, if a user at a site running Imail tried to send one of our users email but mistyped their address, we would send back a "bounce" email message, telling them that the address they sent to is not valid.

But, if the Imail server was configured to reject bounce messages, it would refuse the message, and so the original email would disappear without anybody knowing about it. The recipient wouldn't know because the sender didn't type the recipient's address properly, and the sender wouldn't know because they wouldn't get the rejection notice. That's bad for everybody involved.

In fact, since the sender's system rejects bounce messages, the only way they can ever know for sure if anybody receives email they send is to call and ask! Therefore, we always reject email from servers configured this way, even though it might have been deliverable.

The fix for this is to configure Imail to accept the bounce messages. The Imail server's administrator should turn off the "Refuse NULL <> Senders" option in Imail's "SMTP Security" settings. After making this change it might be necessary to restart the smtp32 service (run Imail administrator, expand the main drop-down, expand local host, select the services folder, click on smtpd32, click the stop button, click the start button).