Outlook: The host yourdomain could not be found - Socket Error: 11001

Email | Updated 2026
Quick Answer

Socket Error 11001 means Outlook cannot resolve the mail server hostname via DNS. Verify the server is set to mail.yourdomain.com (not just yourdomain.com). If you recently changed DNS or nameservers, allow 24-48 hours for propagation. Try flushing your DNS cache: open Command Prompt and run ipconfig /flushdns.

For complete Outlook troubleshooting steps and all error codes, see our full guide:

Common Outlook Email Errors

Correct Email Settings

Most Outlook errors are caused by incorrect server settings. Use these values:

  • Incoming/Outgoing Server - mail.yourdomain.com
  • POP3 Port - 995 (SSL) or IMAP Port - 993 (SSL)
  • SMTP Port - 465 (SSL)
  • Username - your full email address
  • Authentication - enabled for outgoing, SPA disabled

For step-by-step setup: How to Set Up Email in Microsoft Outlook

This article has been consolidated into our Common Outlook Email Errors guide for easier reference.

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