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Sending Emails Generates Error: 503 valid RCPT command must precede DATA.


Why do I receive error "503 valid RCPT command must precede DATA" when attempting to send email?


This usually is a result of the mail server requiring authentication.

If you are using Outlook 2003, here are the steps to enable authentication:

Watch the Outlook 2003 Tutorial!

  1. Open Outlook
  2. Go to Tools | Email Accounts
  3. "View or change existing e-mail accounts" should already be marked

  4. Click Next
  5. Select the Account with the trouble and click Change
  6. Click on More Settings
  7. Click on the Outgoing Server Tab
  8. Click "My outgoing server (SMTP) requires authentication" and make sure "Use same settings as my incoming mail server" is selected
  9. Click on the Advanced Tab
  10. Set "Outgoing server (SMTP):" port to 26
  11. Click OK and then Test Account Settings
  12. If everything is fine and reports no errors,
    • Click Close.
    • Click Next.
    • Click Finish.
  13. If an error does occur, it will switch to the Errors tab and display the error
Note: If you are still having errors, make sure your login username is your full email address and that the password is correct.
Knowledgebase Article 203,245 views bookmark tags: connect email send unable (updated 1763 days ago)

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