Outlook Error 0x800CCC0E: Connection to Server Failed
This error typically occurs when wrong smtp port number. Below you'll find 5 proven fixes to resolve it.
What Causes Outlook Error 0x800CCC0E?
Outlook error 0x800CCC0E (Connection to Server Failed) can be triggered by several issues:
- Wrong SMTP port number
- Firewall blocking port 587 or 465
- ISP blocking outgoing email ports
- SSL/TLS encryption mismatch
- Authentication not enabled
How to Fix Outlook Error 0x800CCC0E — Step by Step
Verify SMTP settings
Outlook > File > Account Settings > double-click account > More Settings > Advanced tab.
Outgoing (SMTP): Port 587, Encryption: STARTTLS
If that fails, try Port 465, Encryption: SSL/TLS
Enable SMTP authentication
Account Settings > More Settings > Outgoing Server tab > Check 'My outgoing server (SMTP) requires authentication' > Select 'Use same settings as incoming mail server'
Check Windows Firewall
Windows Security > Firewall > Advanced settings > Outbound Rules > New Rule > Port > TCP 587 > Allow. Also add Outlook.exe to allowed apps.
Test with different port
If port 587 gives this error, try port 465 with SSL. If both fail, try port 25 (some ISPs still use this). Each provider has specific requirements.
Disable antivirus mail scanning
Temporarily disable your antivirus to test. If Outlook works with antivirus off, find the email scanning feature in your antivirus and add Outlook as an exception.
Still Getting Error 0x800CCC0E?
IT Cares can diagnose and fix this error remotely — usually in under 30 minutes.
Frequently Asked Questions
What does 0x800CCC0E mean?
Outlook can't establish a connection to the outgoing mail (SMTP) server. You can receive emails but can't send them.
Why can I receive but not send?
Receiving uses IMAP/POP3 (different ports). Sending uses SMTP. Error 0x800CCC0E specifically affects the SMTP connection — usually a port or authentication issue.
What port should I use for SMTP?
Modern standard is Port 587 with STARTTLS encryption. Alternative: Port 465 with SSL. Port 25 is outdated and blocked by most ISPs. Check your email provider's documentation.
Can my ISP block sending email?
Yes. Some ISPs block port 25 and sometimes port 587 to prevent spam. Contact your ISP or use port 465. Alternatively, use your ISP's SMTP server for sending.
Why does Outlook work on WiFi but not office network?
Your office firewall or network may block SMTP ports. Contact your IT department to whitelist ports 587 and 465 for Outlook.
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