How To Fix Smtp Error Code 550?

The SMTP error code 550 indicates that the email has failed to deliver to the recipient’s mailbox. The causes of the error include incorrect recipient email address, firewall blocking, expired or inactive recipient email server, and SMTP authentication failure. If you wish to fix the SMTP error 550, follow the below-mentioned troubleshooting methods.



  • Step : 1 Check whether your recipient’s email server is active.
  • Step : 2 While composing a new email, check whether you have entered the correct email address in the To field.
  • Step : 3 You can verify it using third-party software.
  • Step : 4 Make sure that you have not entered the email address with spaces.

Method: 2

  • Step : 1 On your PC, check whether you have enabled the firewall or Anti-Spam filters.
  • Step : 2 If you have installed any security software, launch it and access to the Protection window.
  • Step : 3 Toggle off the Anti-Spam button to disable the protection.
  • Step : 4 Disable the in-built firewall that blocks your email client from sending emails.
  • Step : 5 After disabling the firewall protection, try to send a test email to check if the SMTP error 550 has been resolved.
  • Step : 6 Follow these steps we can execute that how to fix Smtp error code 550.

Method: 3

  • Step : 1 Check whether your mail server IP address or domain is blacklisted using tools like Real-time blacklist, DNSBL, or RBL.
  • Step : 2 The SMTP error 550 might also be a reason for the rejected emails from the blacklisted domains.
  • Step : 3 Open the MX Lookup page and type the email domain in the required field.
  • Step : 4 Click the MX Lookup button to display the details of the email domain.
  • Step : 5 Copy your email domain and paste it in the text box.
  • Step : 6 Click the Blacklist Check button to view the blacklisted emails.
  • Step : 7 If your email domain is blacklisted, try using another email client to send emails from your PC.
  • Step : 8 Perfrom these steps we can execute that how to fix Smtp error code 550.

Method: 4

  • Step : 1 If you are using the Outlook software as the email client on your PC, you can fix the SMTP error by enabling the SMTP authentication.
  • Step : 2 In the Outlook window, click the Tools tab and select Account Settings.
  • Step : 3 Choose your email account
  • from the displayed list and click the Change button.
  • Step : 4 In the Change Email Settings window, click the More Settings button.
  • Step : 5 In the Internet Email Settings window, navigate to the Outgoing Server tab and check the My outgoing server (SMTP) requires authentication checkbox.
  • Step : 6 Click the Use same settings as my incoming mail server radio button and click the OK button.
  • Step : 7 By using these steps we can execute that how to fix Smtp error code 550.
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