Yahoo Inc
Known for its freemail services AOL and Yahoo, they provide a detailed Postmaster page with contact options for investigating false-positive spam verdicts. Some senders may also qualify for their "Email Marketing Data Feeds" with detailed insight on performance in the inbox.
Domains
yahoo.com · aol.com · verizon.net
Codes
421 · 450 · 451 · 452 · 501 · 550 · 552 · 553 · 554
- 421↑
421 Service not available, closing transmission channel
This indicates that the domain is not currently accepting email.
421 Max message per connection reached, closing transmission channel
421 4.7.0 [TSS04] Messages from 0.0.0.0 temporarily deferred due to unexpected volume or user complaints - 4.16.55.1; see https://postmaster.yahooinc.com/error-codes
This could indicate one of few problems, either that your emails are generating an excessive amount of complaints from Yahoo users or Yahoo is seeing unsual traffic patterns from your mail servers. It could also mean that your email content contains objectionable content or show characteristics indicative of spam. Another possiblity is that your IP has a poor reputation
- 450↑
450 User is receiving mail too quickly
The email address is currently receiving an email at a high rate. Sending email in the future will most likely be successful.
- 451↑
451 example.yahoo.com Resources temporarily unavailable. Please try again later [#4.16.1].
The sender's domain is currently unable to accept this message. Sending email in the future will most likely be successful.
451 4.3.2 Internal server error
- 552↑
552 1 Requested mail action aborted, mailbox not found
Treat this bounce as a 'bad-mailbox'. Experience has shown that the email address is invalid and should not be sent to in the future.
- 553↑
host xx.yahoodns.net [x.xx.xx.xx] SMTP error from remote mail server after MAIL FROM:<user@example.com> SIZE=2022: 553 5.7.1 [BL21] Connections will not be accepted from x.xx.xx.xx, because the ip is in Spamhaus's list; see http://postmaster.yahoo.com/550-bl23.html
host xx.yahoodns.net [x.xx.xx.xx] SMTP error from remote mail server after MAIL FROM:<user@example.com> SIZE=2022: 553 Mail from x.xx.xx.xx not allowed - 5.7.1 [BL23] Connections not accepted from IP addresses on Spamhaus XBL; see http://postmaster.yahoo.com/errors/550-bl23.html [550]
- 554↑
554 delivery error: dd This user doesn't have a example.com account (example@example.com) [-9] - example.yahoo.com
554 delivery error: dd Sorry, your message to example@example.com cannot be delivered. This mailbox is disabled (554.30). - example.yahoo.com
Yahoo email addresses are used for lots of different services -- not just for receiving email. This bounce means that while this recipient is not using Yahoo's email service, the address itself exists for login purposes for other services. The best option is suppress this email address from your lists, as it hasn't used its inbox in a very long time (if ever).
554 delivery error: dd Requested mail action aborted - example.yahoo.com
554 5.7.9 Message not accepted for policy reasons. See https://postmaster.yahooinc.com/error-codes
554 Message not allowed - [PH01] Email not accepted for policy reasons. Please visit https://postmaster.yahooinc.com/error-codes
This rejection occurs out of suspicion that the message or sender is phishing. Review the URLs and images in your content. Once investigated and you can verify your messages are safe, you can request a review from Verizon's support team.
554 Message not allowed - Headers are not RFC compliant[291]
554 Message not allowed - [299]
554 delivery error: dd example@example.com is no longer valid. [-20] - example.yahoo.com