Why do mail servers get blacklisted?

In this guide I’m going to explain why it’s common for mail servers to get blacklisted, and what you can do if your own server has been blacklisted. For instance you can request a delisting from a blacklist.

What is a blacklist?

Depending on who you ask, most people who attempt to track the global level of spam being sent, estimate anywhere between 80%-95% of all email transmitted daily on the Internet is spam.

That means that simply relying on manually going through all of your own email, is not the most efficient method for weeding through spam messages anymore these days.

As such there are public blacklists of mail servers that have been relaying spam. This allows other mail servers to check if an email is from a server’s IP address that might have possibly been flagged for sending spam in the past.

For instance you can use our blacklist check tool to check if your server is currently listed on any public blacklists.

Why is my server on a blacklist

It’s not uncommon for a mail IP address to end up on a public blacklist, especially on a shared server. It could be due to overall volume of mail coming from that server, or messages seem to have characteristics of spam in them.

Another common cause is email forwarders. If you have [email protected] forwarding to [email protected], if [email protected] is spammed, our mail server could forward that onto Yahoo.

Their servers might see our mail IP address as relaying the spam message to their server, even though it wasn’t the originating server of the spam.

Working around blacklisting problems

We monitor email queues for signs of delivery issues with major email providers. If you’re having an issue emailing a certain provider and you need to get a message sent out urgently I would recommend following the steps in my guide on sending mail via Gmail when server IP is blocked to still get your message out in a timely manner.

After that, typically you’d want to request to have the mail server’s IP address de-listed from any blacklists that it’s currently on. In order to do this you can read my guide on requesting a delisting from a blacklist.

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39 thoughts on “Why do mail servers get blacklisted?

  1. We recieve email from a domain that was blacklisted . When we now get their mail at the bottom of the letter is a legal disclaimer . Shoul we be concerned that the sender is in or has been in legal trouble over their use of email (IE sending malicious programs etc) ?

    1. I would not be too concerned. It seems like their system was blacklisted and their disclaimer was added for security. However, it would be best to contact them to confirm this.

  2. 5001.newipdns.com rejected your message to the following e-mail addresses:

    [email protected] ([email protected])

    5001.newipdns.com gave this error:
    Your message to <[email protected]> was classified as SPAM. Please add more content, cut down on HTML links, use fewer naughty words etc. Also, ask your IT dept to make sure your mailserver has REVERSEDNS, SPF, DKIM, and is not on any black lists. Your score: 120


    A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.

    1. The server you are sending to thinks the message is spam. You need to follow their recommendations to get the email through their spam filters. This includes adding more content such as text, removing HTML links, and changing the words you are using (profanity is often seen in spam emails). You should make sure you have SPF and DKIM records set up. Also, it could be helpful to review MXToolBox to ensure your email server is not on any blacklist.

  3. our local school board domain was recently blacklisted by the entire hotmail mainframe for spamming . Since this is an established domain that has been online for years should we be concerned about spyware/virus/worm distribution ?

    1. Hello Wondering,

      Since your domain has been blacklisted, you should take the steps to have it de-listed. This includes having your website inspected for possible spam scripts, and malware. Generally, blacklists have more to do with the malware and spam than the virus/worm/spyware distribution, though, the end sites that are linked can definitely lead to them. If you’re on a public blacklist, you should definitely work with your host in order to get that issue resolved as soon as possible.

      If you have any further questions or comments, please let us know.

      Arnel C.

    1. You would have to review the bounced/returned emails to determine the specific blacklist you are listed on. Then, you can request delisting, or possibly rotate the mail IP if it is caused by a blacklisted address.

      Thank you,

  4. I have got a registered domain.

    Plus i have got smtp hosted on a cloud.

    But whenever i sent emails in bulk they get black listed.

    What can be the issue?

    1. Hello Shahzaib Khan,

      Sorry for the problem with the black listing. When you do get blacklisted, you can inquire from the service that blacklisted you for an explanation. They can give you specific reasons. There may be different guidelines for services that perform blacklisting. However, you can see a good guideline by reviewing the CAN SPAM Act compliance guide.

      I hope this helps to answer your question, please let us know if you require any further assistance.

      Arnel C.

  5. hi

    about 6 or so of my e-mails have suddenly stopped. I contacted one, they said my e-mail provider had blacklisted it, they said  had sorted it, so should be ok. how can I sort the others out myself please?


    malcolm pendrey

    1. Hello Malcolm,

      Please contact our support department with the bounceback errors and they will remove the server from the blacklists if you are on a shared server. On a VPS+ you would have to contact each blacklist company regarding the block and request to be removed.

      Best Regards,
      TJ Edens

  6. I have exchange server.I am configure mail in Desktop,mobile and also access through web.What happen IF someone send a mail from differenent mail id like gmail or any mail id.But in my Exchange server domain.Receiving time difference  between to receive a mail in same mail id but access a mail via a different way.Ex:-If someone send a mail from gmail at 10.30AM.MY mail ID is confiured in my mobile.I am reciving this mail at 10.32AM.And same mail id is confiure in my pc but what happen  i am reciving same mail  at 10.00PM night.

    1. Rohit, we don’t work with Exchange Servers, so we won’t be able to help you with your questions. Sorry about that.

  7. If someone sending a mail from different mail id  receiving time gap between access through web,configure mail and configure mail in mobile in my Exchange server domain.

  8. Buenas Tardes, necesito que me apoyen ya que he revisado desde la mañana todas las blacklist y ya no aparecemos en ninguna pero al querer enviar correos a dos dominio especificos me llega un correo indicando que no se pudo enviar por lo siguiente:


    • Mensaje 1

    A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

        host dcmxppheip005.imr.gm.com []

        SMTP error from remote mail server after initial connection:


        554 Connections from this sending hostname vps6033.inmotionhosting.com, IP address of: are being rejected due to low SenderBase Reputation score (below -1). Your SenderBase organization:


        625402. See https://www.senderbase.org/ for more information.

    • Mensaje 2:

    This message was created automatically by mail delivery software.


    A message that you sent could not be delivered to one or more of its

    recipients. This is a permanent error. The following address(es) failed:


        host mailhost.bnpparibas-pf.com.mx []


        SMTP error from remote mail server after initial connection:


        554 Your access to this mail system has been rejected due to the sending

    MTA’s poor reputation. If you believe that this failure is in error, please


    contact the intended recipient via alternate means.


    Agradezco su pronta ayuda – Grupo DC – IP

    1. It appears the sending server’s IP has a bad reputation. Since this is one of our servers, you will want to forward that bounceback email to our Live Support team to have them review the situation and make any corrections.

      Kindest Regards,
      Scott M

  9. MAils bouce back issue…..

     [email protected]
        host mx2.supremebox.com []
        SMTP error from remote mail server after RCPT
    TO:<[email protected]>:
        550 Sender host (bh-in-9.webhostbox.net) blacklisted at ivmURI
    ------ This is a copy of the message, including all the headers. ------
    Return-path: <[email protected]>
    Received: from localhost ([::1]:48444 helo=webmail.goldentulipbangalore.net)
            by bh-in-9.webhostbox.net with esmtpa (Exim 4.85)
            (envelope-from <[email protected]>)
            id 1ZizoO-001hPL-EH
            for [email protected]; Mon, 05 Oct 2015 07:04:00 +0000


    1. Hello pradeep,

      The error message says that the sending server (webhostbox.com) is on a blacklist and thus can’t sent to any server that checks that list. You will want to contact them to have their team get the server IP delisted.

      Kindest Regards,
      Scott M

    1. Hello vishnu,

      Thank you for contacting us. We are happy to help you troubleshoot, but it is not clear what you are asking.

      Please provide some additional information, on what you are trying to do.

      Thank you,

  10. dear john, thanks for your reply. i bought this domain on go daddy and used joomla to devalope a site. now after that issue when i open forum.joomla.org it says your ip has been blocked for spamming. the email addresses were also halted and did not worked and website showed that something good is going to be on soon, instead of my webpage.


    1. Hello Muhammad ALi,

      Thank you for contacting us. If you are seeing the blocked message on forum.joomla.org, you should contact them. They are the only ones who can unblock you from that site.

      If you can provide a link to your website, we will be happy to test further.

      Thank you,

  11. hello

    my joomla site got banned. apprantly the person i trusted to devalop my site used it for spamming. can anyone guide me how to restore it or appeal?

    1. Hello Muhammad Ali,

      Thank you for contacting us today. We are happy to help, but will need some additional information. Where did you get banned?

      Can you provide an example or link to the banned message or site?

      Thank you,

  12. Hi, I’ve got a client whose email has the words drugtreatment in it. None of their emails go through consistenly. We are trying to figure out if they are blacklisted or it there is a tool to help them tell or get off the blacklist. Because there are questionable drug treatment spam emails out ther could those word in their email be causing the problems, they are a reputable treatment centre…with maybe an unfortunate name?

    1. Hello Myriah,

      It most likely is just the case of having an unfortunate name as most spam filters look for the words drugs specifically. You can check to see if they are listed on any blacklist by submitting their domain here to mxtoolbox.com.

      Best Regards,
      TJ Edens

  13. Oh, Too cool! You mean I have a specific IP address because I use VPS. So cool. I didn’t realize that’s how it works. 

    Thank you so much, John Paul. 🙂

  14. Thanks, Arnel!

    I didn’t know VPS used my IP address. How does InMotion Hosting know my IP address?


    1. Karen,

      Thank you for your question. If the email for your domain name is hosted on our servers, our System Administrators actually assign the IP that is used for transmitting email.

      If you have any further questions, feel free to post them below.
      Thank you,

  15. I haven’t begun to use it yet. The question is general in nature. Am I less likely to get black list problems b/c I have vps?

    1. Hello Karen,

      Since you’re using your own IP address for the VPS, there is definitely a lower probability that you server would get blacklisted. As long as you’re not sending out lots of email that don’t meet the CAN SPAM standards, then you shouldn’t have a problem

      I hope this helps to answer your question, please let us know if you require any further assistance.

      Arnel C.

    1. Hello Karen,

      Are you getting bounce back emails when you try to send these emails?

      Best Regards,
      TJ Edens

  16. Hi,


    I am a freelance website design and have a server where I host some websites. one of my clients is experiencing their emails (not marketing broadcasts) hitting reciepients spam filters and not successfully landing in the inbox.


    They have been told that because they have the website’s address on the email footer, that my server is the reason why their emails are not getting through.


    I dont host any emails, it’s literally just for hosting some WordPress websites.


    I’ve run a blacklist check and my web server is listed, but its on a small listing (not one of the major ones). 


    Could this be the cause or are they looking for an excuse because their mail server has been blacklisted?

    1. Typically, being listed on a blacklist would lead to an overall rejection if the recipient uses that blacklist and not simply go to the spam folder. Unfortunately, the specific reasoning that the message is being send to the recipient’s spam folder would only be known my the recipient’s mail provider, but it is usually due to something in the content of the message, or that email address/domain being flagged somewhere on their server. Try sending the message with different content, as well as from other email addresses on the domain to better identify what may be causing it.

  17. People get this when they try to email me or when I email my self it’s not 100% of the time

    Please fix it 801-521-7000

     A message that you sent could not be delivered to one or more of its

    recipients. This is a permanent error. The following address(es) failed:

    1. Hello Philip,

      Thank you for your question. Since this is a common error when an email address is mis-spelled, I recommend checking the spelling first.

      There are many reasons an email might fail, they must be handled on a case-by-case basis. We would need to see the full failure message to troubleshoot the issue.

      Our bounceback parser tool may help review the returned message.

      Since this is our public forum, you would have to contact Live Tech Support, if you do not want to post the full returned email online.

      If you have any further questions, feel free to post them below.
      Thank you,


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