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Introduction

This error occurs when attempting to send email from a domain that is not authorized for your SMTP user account.

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Example Error Message

Here’s what this error looks like: 
[email protected]
   host relay.jetsmtp.net [103.173.0.0]
   SMTP error from remote mail server after end of data:
   550 [ACL] Blocked. See https://reports.jetsmtp.net/?id=000000000000000000&auth=smtpuser

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What Does This Mean?

Our access control system has blocked your email because:
  • The sending domain is not authorized for your account
  • Your SMTP credentials don’t have permission to send from this domain
  • Domain authentication hasn’t been properly configured

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How to Fix This Error

  1. Verify the “From” address matches an authorized sending domain
  2. Check your account settings to see which domains are authorized
  3. Add the domain to your account through the dashboard
  4. Ensure proper SPF and DKIM records are configured for the domain

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Prevention

To avoid this error in the future:
  • Only send from domains that are authorized for your account
  • Keep an updated list of your approved sending domains
  • Request domain authorization before attempting to send
  • Regularly review your account’s domain settings