You see the error 0x800CCC0E when Outlook cannot send your email. This error specifically means Outlook failed to connect to your outgoing mail server. It stops all outgoing messages while incoming mail may still work. This article explains why this connection fails and provides the steps to fix it.
Key Takeaways: Fixing SMTP Connection Error 0x800CCC0E
- File > Account Settings > Server Settings: Verify your SMTP server name, port number, and encryption method match your email provider’s requirements.
- Windows Security > Firewall & network protection: Check if Windows Defender Firewall or a third-party security suite is blocking Outlook’s connection to port 587 or 465.
- Control Panel > Internet Options > Advanced > Reset: Restores Windows Internet and security settings to default, which can resolve underlying Winsock catalog corruption.
Why Outlook Cannot Connect to Your SMTP Server
Error 0x800CCC0E is a network-level error. It occurs when Outlook’s request to start a session with the Simple Mail Transfer Protocol server is rejected or times out. The SMTP server is responsible for sending your emails. A mismatch between your Outlook account settings and the server’s requirements is the most common cause.
Modern email providers require secure, authenticated connections. If you are using an old port like 25 without encryption, the server will refuse the connection. Antivirus software or Windows Firewall can also incorrectly identify the secure connection attempt as a threat and block it. Less often, corruption in the Windows network subsystem can prevent any application from establishing the correct sockets for communication.
Understanding SMTP Server Requirements
Most consumer and business email services no longer allow plain text SMTP on port 25. They mandate Submission ports: port 587 with STARTTLS encryption or port 465 with SSL/TLS encryption. Your account must also use authenticated SMTP, meaning your full email address and password or an app-specific password are required to send mail. Using an incorrect authentication method will also trigger this error.
Steps to Resolve the SMTP Connection Error
Follow these steps in order. Start by checking your account settings, as this fixes the issue in most cases.
Method 1: Verify and Correct Your Account Settings
- Open Outlook Account Settings
Go to File > Account Settings > Account Settings. Select your email account and click Change. - Check Outgoing Server Information
In the Change Account window, click More Settings. Go to the Outgoing Server tab. Ensure “My outgoing server requires authentication” is checked. Usually, “Use same settings as my incoming mail server” is correct. - Update Server Ports and Encryption
Go to the Advanced tab. Find the Outgoing server (SMTP) field. Change the port to 587. Under “Use the following type of encrypted connection,” select STARTTLS. For providers like Gmail that use SSL, you may need port 465 and SSL/TLS. Click OK. - Test the Connection
Click Next in the Change Account window. Outlook will test your account settings. If the test passes, click Close and then Finish. Try sending a test email.
Method 2: Check Windows Firewall and Antivirus
- Temporarily Disable Third-Party Firewall
If you use Norton, McAfee, or similar, open its interface and temporarily disable its firewall protection. Try sending an email in Outlook. If it works, reconfigure the firewall to allow Outlook.exe. - Allow Outlook in Windows Defender Firewall
Open Windows Security via the Start menu. Go to Firewall & network protection > Allow an app through firewall. Click Change settings. Find Microsoft Outlook in the list and ensure both Private and Public checkboxes are checked. If not listed, click Allow another app to add Outlook.exe.
If the Error Persists After Checking Settings
If correcting your account settings and firewall did not work, the problem may be deeper in the system network configuration.
“Test Account Settings” Still Fails on SMTP
If the account test fails specifically on the SMTP send phase, double-check you are using the exact SMTP server name from your email provider. For example, Gmail uses smtp.gmail.com. Also, some providers require you to enable “Less secure app access” or generate an app password if you have two-factor authentication enabled. Log into your email provider’s web portal to verify these security settings.
Outwork Works on Another Network
If you can send email from the same computer on a different network, your primary network may be blocking SMTP ports. Some corporate or public networks block outgoing connections on ports 587 and 465. Contact your network administrator or try using a mobile hotspot to confirm. You may need to use your provider’s webmail or a VPN.
Reset Windows Internet and Winsock Settings
- Open Internet Properties
Press Windows key + R, type “inetcpl.cpl”, and press Enter to open Internet Properties. - Reset Advanced Settings
Go to the Advanced tab. Click the Reset button under “Reset Internet Explorer settings.” Check the box for “Delete personal settings” and click Reset. This resets underlying security and network components. - Reset Winsock Catalog via Command Prompt
Search for “Command Prompt,” right-click it, and select Run as administrator. Type the command “netsh winsock reset” and press Enter. Restart your computer when prompted.
SMTP Error 0x800CCC0E vs Related Send Errors
| Item | Error 0x800CCC0E (Cannot Connect) | Error 0x800CCC0F (Server Rejected) |
|---|---|---|
| Primary Cause | Network blockage or wrong server/port | Correct connection but failed login |
| Server Response | Connection timed out or refused | Server replied with an authentication error |
| Typical Fix | Check firewall, ports, and server address | Correct password or enable SMTP auth |
| Encryption Role | Wrong encryption type blocks the handshake | Encryption works but credentials are wrong |
You can now diagnose and fix the SMTP connection error 0x800CCC0E. Start by verifying your outgoing server port and encryption settings in Outlook. If the problem continues, check for software blocking the connection. For advanced troubleshooting, use the Test Account Settings feature after each change to see which specific step fails. This helps you quickly identify if the issue is with the server, your credentials, or your local network.