Email sent to Yahoo Mail addresses is rejected
Yahoo Mail rarely outright rejects email upon connection. If you're an email administrator, Yahoo recommends that you review the associated SMTP logs for any of the errors below:
- "553 VS99-IP1 deferred" - This error means your SMTP connection was rejected.
- "451 VS1-IP Excessive unknown recipients - possible Open Relay (#4.1.8)" - means the email was deprioritized (see our guidelines on avoiding deprioritization)
- "451 VS1-MF Excessive unknown recipients - possible Open Relay (#4.4.5)" - means the email was deprioritized (see our guidelines on avoiding deprioritization)
- "554 delivery error: dd This user doesn't have a yahoo.com account ([recipients' userid]@yahoo.com)" - The email didn't go through because the recipient's user ID doesn't exist. You shouldn't retry the message, as it will never complete successfully.
- "421 Resources temporarily unavailable. Please try again later" - The Yahoo Mail servers are temporarily too busy. Your server should try to resend the message after a few minutes.
If you don't see these, or similar error messages, the emails in question aren't being blocked or deprioritized. You should see an SMTP confirmation code similar to "250 ok dirdel" that indicates your message has been delivered.