Getting blocked by hotmail

Discussion in 'Linux VPS/Dedicated - General' started by AlexH, Sep 18, 2014.

  1. AlexH

    AlexH Member

    Ok, so to be honest I didn't think hotmail was still around. But I am getting emails returned from Hotmail. I am getting an error that "part of" my internet service provider is on the block list. The concerning part is that I am getting this error message from two different KH accounts on multiple IP addresses. Several of my clients are also complaining.

    These emails are even getting bounced to people who have my email address in their address book.

    ** I took out my IP, and my email address**

    SMTP error from remote mail server after MAIL FROM:<XXX> SIZE=9994:
    host []: 550 SC-001 (COL004-MC5F18) Unfortunately, messages from (MYIP) weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to
    [email protected]

    Any ideas on how to get this fixed???
  2. esoft

    esoft New Member


    Error Code 550 SC-001 is "Mail rejected by for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help."

    You may point your browser to the following url and initiate a ip unblock process, in most cases they do it in 1-3 days.
  3. Dion

    Dion Member

    I recently had the same problem. I tried using the above URL...not only was the IP block not lifted, I never even received a response from Microsoft.

    I then opened a support ticket here. The IP block was lifted within three hours. :)
  4. AlexH

    AlexH Member

    Thanks all. I submitted the request for one of my IP addresses and I got a response in less than an hour. They advised the block was lifted but it would be monitored. I'll give my second one a try and see if I have the same luck.

    Here's what I got from them:

    We have completed reviewing the IP(s) you submitted. The following table contains the results of our investigation.

    Conditionally mitigated
    Our investigation has determined that the above IP(s) qualify for conditional mitigation. These IP(s) have been unblocked, but may be subject to low daily email limits until they have established a good reputation.

    Please note that mitigating this issue does not guarantee that your email will be delivered to a user’s inbox.

    Ongoing complaints from users will result in removal of the mitigation.

    Mitigation may take 24 - 48 hours to replicate completely throughout our system.

    If you feel your issue is not yet resolved, please reply to this email and one of our support team members will contact you for further investigation.

    Regardless of the deliverability status, recommends that all senders join two free programs that provide visibility into the Outlook.comtraffic on your sending IP(s), the sending IP reputation with and the Outlook.comuser complaint rates.

    Junk Email Reporting program (JMRP) When an user marks an email as "junk", senders enrolled in this program get a copy of the mail forwarded to the email address of their choice. It allows senders to see which mails are being marked as junk and to identify mail traffic you did not intend to send. To join, please visit

    Smart Network Data Services program (SNDS). This program allows you to monitor the ‘health’ and reputation of your registered IPs by providing data about traffic such as mail volume and complaint rates seen originating from your IPs. To register, please visit

    There is no silver bullet to maintaining or improving good IP reputation, but these programs help you proactively manage your email eco-system to help better ensure deliverability to users.

    Thank you, Deliverability Support
  5. phpAddict

    phpAddict Active Member

    I have had Microsoft block my IPs when I was with HG a couple times over the years and I was also issued a block of bad IP addresses when I got my dedi set up here at KH. Trying to reach Microsoft and get them to do anything about the issue is like asking a snail to hurry up. The fastest fix is to change your IPs where your email is sending out, which can be done in your Exim settings. But, you should find out why you were blocked and correct it, otherwise you will just keep getting each IP on your server blocked.

    The problems I've had were usually due to a user forwarding their email on my server to their personal live email account, then they either received too much junk email that was being forwarded or they marked one of the forwarded emails as junk then Microsoft thinks your server is spamming rather than the true source.

    I've also had to monitor the mail queue to find that an email account was compromised, then changed its password to stop the spammers.

    Enforcing password policies so all your users are forced to have good passwords will reduce the chance of the latter issue reoccurring.

    With all that said, I recommend changing your servers emailing IP to quickly begin emailing again, find and resolve the issue that caused it, and continue to get Microsoft to remove the black list of your original IP so you can use it again at some point.
  6. Chris.M

    Chris.M Member

    Heh, on the same topic:

    I'm fairly confident Google's been blocking auto-generated mail from my servers. I don't personally send mail from them, nor does anyone else, but Gmail's system has finally become tired of the email being generated by lfd/CSF (it's sent to me only). It now sporadically arrives or doesn't come at all. I received a set of the famous 550 errors yesterday - does Google have a similar process that one must go through to have these restrictions/blocks removed?

    Funny enough, these emails were very rarely marked as "spam." When they were, I quickly reported them as the opposite. I can't even begin to imagine what the algorithms these guys use look like, let alone how they operate.
  7. KH-Jonathan

    KH-Jonathan Director of Managed Services Staff Member

    Hotmail has become straight up obnoxious with IP blacklistings. We fight a constant battle every day getting IPs de-listed for customers who have never had a malicious email sent from their IP before. The good news is hat they will usually lift them rather quickly, within a couple of hours, but we have to be the one to contact them most of the time as if the contact doesn't come from the owner of the IP space (us) they simply won't respond which is likely why you didn't hear back from them @Dion. When you find yourself listed by Microsoft open up a ticket and we can get the listing lifted for you 98% of the time. Sometimes they refuse for a while.

    We've tried working with them every way possible even joining their JMRP which is a disaster. Any time someone clicks "spam" on a message we get an email about it. Well lets just say that people like using the "spam" button instead of "delete" I guess because most of the emails that get reported this way are clearly legitimate. Hotmail's whole process of this is flawed, but they don't even care.

    Gmail on the other hand has no delisting process @Chris.M but I've always found their automated system to work rather well. If they block/limit you they generally lift it pretty quickly and they usually don't blacklist legitimate folks. If you do end up listed/limited there you simply have to wait it out but this is usually only a day or two in my experience and if you follow all of their email recommendations you won't get listed to start with. Kudos to Google there.
  8. AlexH

    AlexH Member

    Thank you KH-Jonathan. I will definitely open a support ticket for my other account. I appreciate everyone's input, and your willingness to help. Typical KH support.. quick and helpful!
  9. Chris.M

    Chris.M Member

    Jonathan, appreciate the additional information. I've noticed that some email being generated lands right in my inbox as intended and the rest never arrives. I'll keep an eye on it and see if anything changes over the next week. Perhaps I should simply take those lfd notifications and tone them down a notch or two. The messages being "blocked" are primarily brute force notifications and hourly log reports from CSF.
  10. dbltoe

    dbltoe New Member

    Still having our problem with AOL, AT&T and sbcglobal.:mad:
    Have tried on multiple occasions with no resolve.
  11. phpAddict

    phpAddict Active Member

    You'll have better success changing the IP address your emails are going out on. That'll get around the black listing (unless they've blacklisted an entire block of IP addresses). Then find and fix the problem that caused the black listing in the first place (i.e. someone forwarding email from your server to their personal AOL account then marking email as spam). Then you'll have all the time in the world to get the original IP removed from their blacklist.

    EDIT: Oh' and notify support, they'll have an easier time dealing with those behemoths than you will.
  12. KH-DavidL

    KH-DavidL Abuse & Documentation Specialist Staff Member

    Good point and agreed. Support is always available for assisting with such issues as well.

    @Chris.M Are your emails to Gmail getting blocked entirely? Or going to spam?
  13. Chris.M

    Chris.M Member

    It's working perfectly now, but when I last posted they were being blocked outright. They would either drip through sporadically or not arrive at all. There were a few times - prior to the messages being blocked - that they would go to spam. I immediately corrected this and marked them as "not spam."

    Not sure if this ended up helping or it's just a coincidence, but I also specified than any and all mail arriving from the addresses in question should never be marked as spam. Shortly after getting this filter parameter in place, they started to come through again. Now? No issues.
  14. The Lyrist

    The Lyrist New Member

    I assume that you have DKIM and SPF configured for those outgoing email domains in the DNS?
    Sometimes I have seen incidents where some ISPs with aggressive SPAM filtering policy blocking IP or domains with lack of reputation. It is kind like when being rejected for credit simply because one lacks any credit history. Heck, I have seen some of our emails blocked because the email contains links to a newly registered domain by some ISPs.

    You can do a quick check of the reputation of your IP or domains using Return Path's service here:

    The result from my KH IP:
    Insufficient Email Seen

    If your clients need to send out high volume marketing emails, consider using an ESP as they help manage email reputations, etc. for you.

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