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550 Authentication is Required for Relay

When sending emails using Outlook, you may encounter the error:

Error message

Error 550 5.7.1 We do not relay

Error 550 No such user

This is typically caused by incorrect SMTP settings or the need for authentication. Here’s how to fix it:

Click to view the step-by-step guide
  1. Click on the “File” tab in the top-left corner.
  2. Select “Info” from the menu on the left.
  3. Click “Account Settings” and then select “Account Settings” from the dropdown menu.
  4. In the Account Settings window, select the email account you want to configure, then click “Change.”
  5. The “Change Account” window will appear. Click “More Settings”.
  6. In the Internet E-mail Settings window, go to the “Outgoing Server” tab.
  7. Check the box for “My outgoing server (SMTP) requires authentication.”
  8. Choose “Use same settings as my incoming mail server.”
  9. Click “OK” to save the settings.
  10. Click “Next” to test the account settings.
  11. Click “Finish” to complete the configuration.
  1. Open Mozilla Thunderbird on your computer.
  2. Click on the menu button (three horizontal lines) in the top-right corner.
  3. Select “Options” from the dropdown menu.
  4. In the Options window, click “Account Settings” at the bottom of the list.
  5. Select the account you want to configure from the left-hand pane.
  6. Click “Outgoing Server (SMTP)” at the bottom of the left-hand pane.
  7. Select the SMTP server you want to configure from the list and click “Edit.”
  8. In the SMTP Server Settings window:
  9. Enter the "Server Name" for your outgoing mail server.
  10. Set the "Port" (usually 465).
  11. Choose “SSL/TLS” for the connection security if required.
  12. Set the “Authentication method” to “Normal password”.
  13. Enter your “User Name” (full email address).
  14. Enter your “Password” for the email account.
  15. Click “OK” to save the settings.
  16. Click “OK” again in the Account Settings window to apply the changes.
  17. Close the Options window.
  18. Send a test email to ensure the SMTP configuration is working correctly.

Step 1: Enable SMTP Authentication

Ensure that your outgoing mail server requires authentication:

  1. Open Outlook and go to File > Account Settings.
  2. Select your account and click Change.
  3. Click More Settings... and go to the Outgoing Server tab.
  4. Check "My outgoing server (SMTP) requires authentication".
  5. Select "Use same settings as my incoming mail server".

Step 2: Verify SMTP Settings

Ensure that the SMTP server is correctly configured:

  1. Open More Settings... under Account Settings.
  2. Go to the Advanced tab.
  3. Use the correct port number: typically 465 for outgoing mail.
  4. Select the appropriate encryption method: SSL/TLS for port 465.

Step 4: Contact Your Email Administrator

If the issue persists, contact your email administrator to ensure there are no restrictions or further configurations required on their end.