In our continuing efforts to protect our users from unsolicited email, Yahoo! Mail does not accept SMTP connections from IP addresses listed as spam sources on the Spamhaus SBL. If you are seeing this error message, please do not retry sending your message using the same IP address.

If you think that your IP address has been listed in error, you or your email administrator should contact Spamhaus. Once your IP is delisted by Spamhaus, Yahoo! Mail will automatically unblock your IP within 48 hours.