Receiving "421 4.7.1 [TS03] All messages from x.x.x.x permanently deferred" when sending email to Yahoo
This message indicates Yahoo is seeing a high volume of emails from your IP address, which is a characteristic of unsolicited, bulk emailing.
- We do not recommend resending until you check your subscription practices and lists to ensure that messages are sent only to users who have requested it.
- If you are not the administrator of the mail server in question: please contact the administrator.
- If you are an administrator for message content or mailing policy and you have deployed significant changes or you have received this error for more than 48 hours, please review outgoing messages for objectionable content or practices.
- See Yahoo’s recommended guidelines for bulk mail senders and postmasters: we do not disclose further information about our filtering practices.