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Fixing the 550 5.7.1 [CS] Message blocked. error

If you're receiving this error, it means we have detected this email to be a spam. 

What can I do as an end-user if this is a false positive?

Please file a support request with your web hosting provider. 

What can I do as a service provider if this is a false positive?

If your legitimate email message is blocked by MailChannels, an error message is generated and included in the non-delivery report you receive from your mail server when an email is bounced. When you submit a false positive report, our system corrects its behaviour so that similar messages will not be blocked in future.

Please submit a false positive report by sending an email to along with the following details:

  • Sender email address
  • Authenticated username of the sender (for example, x-authuser)
  • Recipient email address
  • Error message
  • Copy of the compromised account notification, if received

To ensure faster response from Support, please provide as much information as possible about the issue.

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    It is completly stupid to block mails with the headline "Medienmitteilung", How should a communication agency send Press releases without mentioning it???

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    this is very bad and its effecting our business i request to end this silly restrictions!!

    my email is being blocked from sending since a week now and still no solution and very slow responding..i really advice to shut this service down!!!

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    Email Status:Blocked (Spam Content)
    Response:550 5.7.1 [CS] Message blocked. If this is a false positive, please report this to your hosting service provider. See

    Please help to remove domain client cannot send email for along time.

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