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✉️ Email Delivery

Documentation, reference material and tutorials for CRM-NG SMTP Email: setup guides for every mail service, troubleshooting, and one article per error message.

Error: Account blocked: malicious behaviour

Updated

By Duane GarnerChief Executive Officer (CEO)
Summarize: Claude ChatGPT View Markdown
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The mail service has suspended your account after its abuse checks flagged activity. Find the cause, secure the site, then ask the provider to review.

Shown by API mailers (any provider that suspends accounts, such as Brevo, SendLayer, Mailgun or SendGrid)

The test result or the error log shows a message such as Account blocked: malicious behaviour or another message containing "malicious" when CRM-NG SMTP sends through a mail service.

This article is for site owners whose mail provider has blocked their account. The exact wording differs between services, but the meaning is the same.

What this error means

Mail services watch for patterns that look like spam, phishing or a hacked account. When they see enough of them, they suspend sending for the whole account. While the block is in place, every request is refused, whatever the key or settings.

CRM-NG SMTP cannot lift the block. Only the provider can, usually after you explain what happened and show it is fixed.

Common causes

  • The site was compromised and used to send spam through your account. Look for unknown admin users, new plugins or files you did not add, and contact forms that send to arbitrary addresses.
  • A contact or registration form was abused by bots, sending large numbers of messages to addresses that do not exist, which drives up bounces.
  • High complaint or bounce rates, for example from sending to an old or bought list.
  • Message content that looks like phishing, such as login links that point to unrelated domains.
  • A sudden jump in volume on a new account that had not built a sending history.
  • Account details at signup that the provider could not verify.

How to fix

  1. Stop the flow

    If you suspect abuse, go to CRM-NG SMTP → Settings → Misc and turn on Stop sending all emails under Do Not Send while you investigate. Test emails can still be sent.

  2. Look at what was sent

    Open CRM-NG SMTP → Settings → Email Log and filter recent messages. Look for unusual subjects, recipients or volumes. The provider's activity log shows the same from its side.

  3. Clean and secure the site

    Remove unknown users and plugins, update everything, change admin passwords and add a captcha or similar check to public forms.

  4. Rotate the key

    Create a new API key at the provider and delete the old one, in case it leaked. Paste the new key in CRM-NG SMTP → Settings → General.

  5. Contact the provider

    Open a ticket with the provider's support. Explain the cause and the steps you took. Ask them to review the block.

  6. Resume and test

    Once they confirm, turn Stop sending all emails off and send a test from CRM-NG SMTP → Tools → Email Test.

Verify it worked

The test page shows "Test email sent successfully! Check your inbox to confirm delivery." Watch the Email Log and the provider's bounce and complaint figures for a few days.

Notes

  • Use Email Rate Limiting in CRM-NG SMTP → Settings → Misc to cap how many emails the site can send per minute, hour or day. A cap limits the damage if a form is abused again.
  • If the provider will not restore the account, choose another mailer, but fix the cause first or the same will happen there.
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