My mail server has been getting the following error from Yahoo's mail servers since about a month:

postfix/smtp[23791]: host g.mx.mail.yahoo.com[] refused to talk to me: 421 4.7.1 [TS03] All messages from [my ip] will be permanently deferred; Retrying will NOT succeed. See http:// postmaster.yahoo.com/421-ts03.html

I have exchanged about 4 emails with Yahoo's support team. The first three seemed like automated messages, and the 4th told me that there is nothing they can do, but if I change my policies I can send them another email in 6 months. They also told me:

However, based on the information you have provided us, we cannot systematically deliver your email to the Inbox at this time. We suggest that you ask your users to set up a filter in Yahoo! Mail to ensure that they get your email messages in their Inbox.

The problem is that my email doesn't even get to their Spam folder. The server won't allow any connections.

I have never sent spam messages, not even newsletters. I only send emails for my new users so they can activate their account. I've also implemented DKIM and told Yahoo about this. I have checked my configuration with http://www.myiptest.com/staticpages/index.php/DomainKeys-DKIM-SPF-Validator-test and it reports that both SPF and DKIM are set up correctly.

What should I do? Basically, I'm losing new users every day. Any help will be appreciated.

P.S.: I apologize if this particular question has already been asked. I searched for it but didn't find it.


7 Answers 7


I've dealt with this frequently for our clients. Unfortunately, you are at a TS03 level which can be harder to get removed.

Here's some tips to get this moving forward:

I am assuming you have ruled out the following:

  • Open Relay

  • Insecure web script being used by hackers/spammers

  • Client sending out large newsletters

Forwarded Emails

Just a special note about this as many people don't realize this can get you blocked.

If your client forwards and email to Yahoo (or AOL, Gmail, MSN etc) and then the user flags the email as spam at their ISP:

Your server's sender reputation is damaged not the original sender.

Since as much as 80% of email is spam, a large percentage of the forwarded emails could be spam. Even at low volumes such a large percentage will get you blocked.

See if any Email Gets Through

You will also want to scan your logs over several days to see if any email gets through. Sometimes a block will be lifted but if you are still sending a high amount of spam, you will get blocked.

If you can update your question with some details on the mail stats, forwarding and other items, perhaps I can provide some more assistance.

As a last resort, you can change your server's IP address, but do this only after you clean up any items that could be triggering their policies.


I had the same problem.

What ultimately worked for me (I have several users forwarding all kinds of personal email via .forward) was to actually become a "Yahoo! Verified Bulk Sender":


It took a couple of days but I haven't had any problems at all ever since. Note that I am not a bulk sender in any usual sense, I just have normal users using normal .forward files.

I know it seems ridiculous, and I was cursing yahoo (or Yahoo!, as I learned) the entire time, but it works after all the workarounds (routing mail through a different ip, server, whatnot) and checking or tweaking extra stuff (DKIM, Domain Keys, SPF records) doesn't...

  • Like I've said, I did complete that questionnaire, and they concluded that they cannot do anything, but I can try again in 6 months.
    – liviucmg
    Feb 26, 2010 at 11:14
  • Ah, I didn't realize your link led to the same place. It took me 4 or 5 tries over those couple of days, all playing dumb and nice. "I don't understand how users can set up a filter to receive my mail if its still queued on my servers. What can I do? Thanks!" etc.. Feb 26, 2010 at 12:35

I know this is an old thread but the problem doesn't seemed to have changed over the last couple of years. My solution, which is kind of radical and probably can't be followed by everyone, is to ban Yahoo. I do not send emails to people with Yahoo accounts and I don't allow people with Yahoo addresses to sign up.

  • In some mailing lists I run, I ban AOL email addresses for similar reasons. Sep 7, 2013 at 20:19
  • Years later ... AOL and Yahoo are parts of the same network now. ^^
    – leopold
    Dec 3, 2019 at 14:11

I had (and have) the same problem - I just 'inherited' an IP in the datacenter for my new mailserver and it was probably an IP from which some spam / crap was sent to Yahoo so it was banned. There are 3 solutions:

  1. ask Yahoo for whitelisting your IP at http://help.yahoo.com/l/us/yahoo/mail/postmaster/bulkv2.html. I did, after 3 weeks of automated responses and one-way communication they confirmed that "they've made appropriate changes to the IP in their database". In fact nothing changed at all and all my (my server) emails are still returned as "deferred".
  2. use 3rd party SMTP (you'll get a different IP and your emails will be delivered properly). There are plenty of services, some of them free to certain amount of sent emails like https://mandrill.com/
  3. the most radical solution - don't play the game of the fool. They don't like you? Don't like them too and simply disallow to e.g. register a new member with @yahoo.com email (and recommend another freemail, there are plenty of much more friendly services). Simply ban Yahoo, the did the same to you.

(P.S. Make sure your email politics fulfills all the standards - you have rDNS, you have DKIM / DomainKeys, you have a PTR record on your domains. All mature freemails will accept your emails then... except Yahoo :-) ).


I had this problem with sending emails to Yahoo when one of our offices got a new internet connection and a new IP address. It seemed that a previous "owner" of the IP address had used it for something that got them banned from the Yahoo mail servers.

As a result, after doing the same thing you did and not getting any help from Yahoo, we set up a Send Connector (in Exchange) so that any emails going to @yahoo.* would be routed through a different mailserver that Yahoo DID accept mail from.


I was going to suggest something very similar to Farseeker. What I've done in the past is to set up IIS SMTP on a new server, configure a new SMTP connector on my Exchange 2003 server for yahoo.com, give it a lower cost then my default SMTP connector, configure the new Yahoo SMTP connector on Exchange to use my IIS SMTP server as a smarthost, configure my smarthost to allow my Exchange server to relay through it and, viola, my emails are then delivered to Yahoo successfully.


Try to check your mail server;s ip address in listed at spamhaus.org

if you find your ip address listed at spamhaus.org , request them to remove your ip address from their database

after remove from ip from spamhuas.org mail will be send from your mail server to yahoo's mail server.

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