Email "Error 550" Meaning

By Derek King

Troubleshoot your Outlook settings to get rid of
i email image by Hao Wang from

Using Microsoft Outlook for email is often a pleasant experience. Every now and then, however, an error may appear on the program, prohibiting you from sending emails. One of these errors is "Error 550." Understanding why this error is sent, and how to fix it is critical to ensuring continued use of Microsoft Outlook.


When a user sends an email to an email address whose domain (the name after the @ symbol, such as is not processed by the Simple Mail Transfer Protocol (SMTP), the SMTP server must connect to another SMTP server to relay the message. If there is an error in relaying the message, your SMTP (outgoing) email server will return your email message with an "Error 550" message.


SMTP is the protocol that many email servers use to send messages across the Internet. When an individual uses an email program such as Outlook that allows storage of e-mail messages on a computer, an SMTP server is required to send email messages. Outlook uses a separate protocol entirely to receive email.


To fix the Error 550, access your Outlook settings. Select "Tools," and then click on "Accounts." Go to the section called "View/Change Email Account" to find the email account that's having problems sending email. View the server information. Check that the outgoing mail server (SMTP) is set to (Replace "yourdomain" with the actual domain name, such as

Select the "More settings" window, and then click on the "Outgoing Server" tab. Ensure that the option "My server requires authentication" for the outgoing server is selected. Save and close all windows. Restart Microsoft Outlook and resend the email.

Another Solution

If the problem persists, your Internet service provider is blocking the email server. ISPs take these precautionary measures to prevent spam on their networks. If this is the case, use the email server that the ISP provides. Contact your Internet service provider directly to get troubleshooting advice specific to your problem.


Use Web-based email services in the meantime to send and receive mail. Also consider using a different email client such as Mozilla Thunderbird if problems persist.