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Author Topic: Delivery Issues with transaction Emails to Yahoo  (Read 1175 times)


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Delivery Issues with transaction Emails to Yahoo
« on: May 20, 2020, 02:27:33 PM »


We're facing an issue even when sending double opt-in transactional emails from PMTA to Yahoo servers at the speed of 20-50 emails we start getting the following message in the queue, which somehow doesn't make any sense because authentication is 100% (SPF, DKIM, DMARC, RDNS) and 100% no Spam complaint or Bounce.

2020-05-19 18:23:18 Error: "421 4.7.0 [TSS04] Messages from xxx.xxx.xxx.xxx temporarily deferred due to user complaints -; see https://help.yahoo.com/kb/postmaster/SLN3434.html" while connected from domain.com (xxx.xxx.xxx.xxx) to mta6.am0.yahoodns.net (xxx.xxx.xxx.xxx)

We've also tried contacting Yahoo's Postmaster team but they provide same replies, not understanding. That it's a simple SMTP connection 1 IP with 1 Domain, processing only transactional emails.

So really what max-connect-rate, max-msg-rate & other setting should we use? Because this is very annoying people not receiving billing, support, etc. emails.

Looking for some urgent help.

Thanks a lot!