The Deliverability Ledger · Yahoo · 2 posts
Yahoo and AOL deferrals
The two refusals Yahoo and AOL send most, 421 [TSS04] for complaints and 554 5.7.9 for policy, and how to clear each.
All 2, newest first
- 554 5.7.9 “Message not accepted for policy reasons” — Yahoo/AOL Fix GuideYahoo's 554 5.7.9 is a hard, policy-based rejection rather than a temporary deferral. Here's what triggers it, why it's different from TSS04, and how to clear it.
- 421 4.7.0 [TSS04] “Messages temporarily deferred due to user complaints” — Yahoo Fix GuideYahoo's 421 4.7.0 [TSS04] response is a temporary, complaint-rate-driven deferral rather than a blocklist. Here's what each part of the bounce means and the exact sequence to clear it.
Other topics
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- GoogleThe Gmail bounces senders hit most (421 4.7.0, 421 4.7.28, 550 5.7.26), the bulk sender requirements, Postmaster Tools, and the way back out of the spam folder.
- BlacklistsHow to tell if you are listed, why IP and domain blacklists catch different things, and what SURBL listings mean for cold email.
- AuthenticationSetting up SPF, DKIM and DMARC step by step, and choosing between a quarantine and a reject policy.
- Cold EmailGetting cold outreach into the inbox without burning the domain it is sent from.
- ReputationThe usual reasons a sender reputation drops, and how to rebuild it.
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