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Dynamics 365 Community / Forums / Customer Insights - Journeys forum / Anti-Spoofing Header L...
Customer Insights - Journeys forum

Anti-Spoofing Header Lockout

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Posted on by Community Member

Hello

We have recently authenticated our domain via the DNS entry and emails are now being sent from our main domain email address. The issue is that our mimecast server is identifying the test send emails as spoofed and rejecting them so they are not delivered.

Some more details:

Rejection Description: Anti-Spoofing Header Lockout

Rejection Information: Rejected by header based Anti-Spoofing policy: tim.harper@investec.co.uk

I presume that we would need to whitelist the sending server, in this case mail04.eur.pb-dynmktge.com - is that correct?

Anybody else had this issue and managed to solve it?

Thanks

Tim

Categories:
Setup and Upgrades
  • ralucad Profile Picture
    ralucad 44 on at
    Anti-Spoofing Header Lockout
    Hi
     
    Did you ever find a solution to this problem?
     
    Thank you
  • Community Member Profile Picture
    Community Member on at
    RE: Anti-Spoofing Header Lockout

    Hi Tim,

    Did you get this resolved?  We are experiencing the same error when sending test emails, however the email is not being rejected for all staff. 

    The email is also not appearing in Mimecast rejections, and Mimecast support are at a loss.  

  • Suggested answer
    megcda Profile Picture
    megcda 2,192 on at
    RE: Anti-Spoofing Header Lockout

    Hi Tim,

    With Mimecast you can easily customize your spam filters . When you see the error “Anti-Spoofing Lockout” it means that an Anti-Spoofing Lockout policy has been triggered. It blocks inbound messages originating from an external source destined to the internal domain, where the external source is masquerading as an internal domain sender.

    Mimecast suggests to create an Anti-Spoofing Policy to exclude the sender's address or IP address.

    https://community.mimecast.com/docs/DOC-3342

    https://community.mimecast.com/docs/DOC-1419

    If you need additional help, our team can also help you to optimize your current anti-spam policy.  Please feel free to raise a support ticket and the team will be happy to help you.

    Thanks,

    Megan

    Please mark as Verified if this answers your question!

  • Vivek_Singh Profile Picture
    Vivek_Singh 385 on at
    RE: Anti-Spoofing Header Lockout

    Hi Tim,

    Never faced this issue as such. Could you please check documentation here  to ensure all the steps are correctly followed.

    Hope this helps!!

    Regards

    Vivek Singh

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