Yahoo blocking my company mail server

For a week now Yahoo has been blocking emails sent from our company mail server.

As most of you know I own CG Design LLC.  Since 2003 we've offered web and email hosting, and have dedicated servers in a data center in Pittsburgh, PA and recently New Jersey.  We are constantly monitoring the servers for attacks, mostly dealing with email-related issues.  We serve both personal and business customers who rely on our servers to be up and running and free of issues.

Over the last week we've had numerous complaints from our customers that they can't send email to any of their clients with Yahoo email accounts.  After looking at the server logs we discovered that Yahoo is blocking email from our server IP address.  The following is the exact messages that appears in the server logs:

Thu 2014-08-28 08:54:15: <-- 421 4.7.1 [TS03] All messages from will be permanently deferred; Retrying will NOT succeed. See

As the owner, I personally took on the responsibility of handling the issue, and have reached out to Yahoo to resolve this issue.  The frustrating part is that there's no way to call Yahoo, as all of the numbers that I have found and tried I've been on hold for over an hour each time with no live person to talk to.  I can't send them an email because...well...they're blocking our mail server.  So, I took to Twitter and received a general response to use an online form that I already filled out.  I responded to their tweet, only to receive nothing in return.

At 3:55pm PST I received a response from my online form submission stating that they "made appropriate changes to this IP address in our database".  So, I logged into our mail server and attempted to re-send two of the emails that had failed.  To my dismay I received the same message that the server had been blocked.  So, I thought maybe it would take some time for the change to take effect.  This morning I made another attempt, and the above message is what I received.

The sad thing is that our server is not listed on any other spam blacklist, including SpamHaus, McAfee Trusted Source, or any other blacklist that we've been able to find.  All of the tests check out for DNS issues, MX records, etc.  There is absolutely no reason for Yahoo to be blocking us, but yet they have made it impossible for us to continue doing business with our customers who rely on us to send email to their clients with Yahoo-supported accounts.  And, this isn't just people with email addresses.  It's also people with SBCGlobal addresses and a number of other domains.

Believe me when I tell you that we have spent a considerable amount of time fighting spam, both incoming and outgoing.  I am constantly adjusting the security settings for incoming mail filtering because I'm personally tired of getting 50-60 messages a day trying to get me to buy windows, switch insurance companies, or divorce my wife for a new Russian bride that it waiting for me.  And as a result I have implemented a very strict policy for any of my customers who want to initiate an email campaign for marketing purposes.  I personally approve or deny each request, and once the campaign kicks off I am glued to the server watching its every move.  If something doesn't look right, I immediately stop the campaign and notify my customer.

Only once has a spammer been able to infiltrate our server, and it was used to attempt to send 68,000 unsolicited messages before it was caught.  This was due to one of our clients giving their username and password out to someone they shouldn't have.  The server was immediately suspended, and the majority of the 68,000 emails were permanently deleted.  We adjusted the security settings to be even more stringent and haven't had an issue since.

As you can see I am extremely frustrated by this whole situation, and it's severely affecting our business.  We already lost 2 customers, and a third one is threatening to leave by the end of the week if it's not resolved.  Yahoo isn't being much help, and at this point I don't know what more I can do.


**UPDATE** - 8/28/14 @ 12:22pm EST

Right now we have 21 emails in the retry queue of our mail server that are waiting to be delivered to business clients of 3 of my customers.  This is completely uncalled for considering that this issue is supposedly fixed according to Yahoo.  Apparently they noticed on Twitter again, as I just got a response that they have "escalated this to out Postmaster team to review further".  I surely hope this is true because I'm waiting for a phone call that we just lost another hosting customer.

If you are reading this as a Yahoo employee, the incident numbers are 140826-014905 and 140828-014342.  My contact information is included and I am eagerly waiting for you to contact me.


**UPDATE** = 8/28/14 @ 1:54pm EST

Just received the following message from John at Yahoo Customer Care:

Hi Chris, 

I want to add some additional information to ensure you're updated on the findings of our investigation. 

It appears your domain and IP address are on 3rd party blacklists not associated with Yahoo.  Therefore, we are unable to resolve your issue.  You’ll need to address this blacklisting immediately, as it may be contributing to your delivery issues. 

I highly recommend that you begin an online research for your domain’s DNS/SMTP records.  It’s widely known that negative domain information can contribute to your mail being blocked or categorized as spam.  

Thanks for your patience. 



Yahoo Customer Care 

Go mobile with Yahoo, so you are always in the know!


This is complete garbage, as I have ran NUMEROUS tests for blacklisting and EVERY one of them have come back negative. If this was the case, why didn't John provide the names of the lists that our server is supposedly on?  AND obviously he didn't read my original comments or he would know that we've been hosting websites and email since 2003.  Of course I am fully aware of the effect of "negative domain information".

Here's just ONE of the tests that we've ran:

Furthermore, our server logs specifically show the IP address and a URL pointing to a Yahoo site.  In tracing the IP addresses that are listed they are all owned and registered to Yahoo Broadcast Services or Yahoo.  So how can he possibly say that it's not Yahoo that's blocking us?

Here is the server log:


Thu 2014-08-28 09:40:16: Attempting SMTP connection to []
Thu 2014-08-28 09:40:16: Resolving A record for [] (DNS Server:
Thu 2014-08-28 09:40:17: * TTL=(0) A=[]
Thu 2014-08-28 09:40:17: Attempting SMTP connection to []
Thu 2014-08-28 09:40:17: Waiting for socket connection...
Thu 2014-08-28 09:40:17: *  Connection established ( ->
Thu 2014-08-28 09:40:17: Waiting for protocol to start...
Thu 2014-08-28 09:40:17: <-- 220 ESMTP ready
Thu 2014-08-28 09:40:17: --> EHLO
Thu 2014-08-28 09:40:17: <--
Thu 2014-08-28 09:40:17: <-- 250-PIPELINING
Thu 2014-08-28 09:40:17: <-- 250-SIZE 41943040
Thu 2014-08-28 09:40:17: <-- 250-8BITMIME
Thu 2014-08-28 09:40:17: <-- 250 STARTTLS
Thu 2014-08-28 09:40:17: --> STARTTLS
Thu 2014-08-28 09:40:17: <-- 220 Start TLS
Thu 2014-08-28 09:40:17: SSL negotiation successful (TLS 1.0, 256 bit key exchange, 128 bit  encryption)
Thu 2014-08-28 09:40:17: --> EHLO
Thu 2014-08-28 09:40:17: <--
Thu 2014-08-28 09:40:17: <-- 250-PIPELINING
Thu 2014-08-28 09:40:17: <-- 250-SIZE 41943040
Thu 2014-08-28 09:40:17: <-- 250 8BITMIME
Thu 2014-08-28 09:40:17: --> MAIL From:<> SIZE=3469
Thu 2014-08-28 09:40:17: <-- 421 4.7.1 [TS03] All messages from will be permanently deferred; Retrying will NOT succeed. See
Thu 2014-08-28 09:40:17: --> QUIT

And here is the IP trace report.  Check it out for yourself to see that the server belongs to Yahoo:

So, according to John's response, it can only be determined that Yahoo is using some 3rd party blacklist that no one knows about, or they simply don't want to deal with the issue.

At this point I'm ready to launch a campaign involving the news media and all of the major tech blogs.  This is completely uncalled for, and obviously Yahoo doesn't want to do anything about it.


28. August 2014 09:27 by Admin | Comments (0) | Permalink