You see error 0x800CCC67 when trying to send an email from Outlook. This error indicates a failure in the SMTP protocol during the sending process. It prevents your message from being delivered to the outgoing mail server. This article explains the common causes and provides steps to resolve the SMTP connection issue.
Key Takeaways: Fixing Outlook SMTP Error 0x800CCC67
- Account Settings > More Settings > Outgoing Server: Verify the correct authentication method is selected for your email provider.
- Account Settings > More Settings > Advanced: Confirm the outgoing SMTP port number matches your provider’s requirements.
- Windows Security > Firewall & network protection: Check that your firewall or antivirus is not blocking Outlook’s connection to port 587 or 465.
Why Outlook Shows SMTP Error 0x800CCC67
Error 0x800CCC67 is an SMTP protocol error. It occurs when Outlook cannot successfully communicate with your outgoing mail server. The SMTP server is responsible for sending your messages. A failure here means your email never leaves the Outlook application.
The most frequent cause is incorrect authentication settings. Your email account must prove its identity to the SMTP server. If the login method or credentials are wrong, the server rejects the connection. Another common reason is a blocked network port. Firewalls or security software can prevent Outlook from accessing the required SMTP port.
Understanding SMTP Server Requirements
Every email provider uses specific SMTP settings. These include a server address, a port number, and an encryption type. Common ports are 587 for TLS and 465 for SSL. Using the wrong port for your provider’s setup will cause this error. The server address is also critical. For example, Gmail uses smtp.gmail.com, while Outlook.com uses smtp-mail.outlook.com.
Steps to Resolve Error 0x800CCC67 in Outlook
Follow these steps in order to diagnose and fix the sending error. Start by verifying your account settings.
- Open Outlook Account Settings
In Outlook, go to File > Account Settings > Account Settings. Select your email account from the list and click Change. - Check Outgoing Server Settings
In the Change Account window, click More Settings. Go to the Outgoing Server tab. Ensure the box for “My outgoing server requires authentication” is checked. Select “Use same settings as my incoming mail server” or log on with specific credentials as required by your provider. - Verify Advanced Port and Encryption Settings
In the More Settings window, go to the Advanced tab. Look at the Outgoing server SMTP port. Confirm this number matches the port specified by your email service. Also, verify the encryption type below the port matches, such as TLS or SSL. - Test the Connection
Click OK to close the windows, then click Next in the Change Account window. Outlook will test your account settings. If the test fails on sending, note the new error code for further troubleshooting. - Check Firewall and Antivirus Software
Open Windows Security via Start > Settings > Update & Security > Windows Security. Click Firewall & network protection. Ensure Outlook is not blocked. Temporarily disable third-party antivirus software to test if it is causing the block, then re-enable it.
Alternative Method: Create a New Profile
If the error persists, your Outlook profile may be corrupted. Creating a new profile can fix underlying data issues.
- Open Mail Setup
Close Outlook. Open the Windows Control Panel and search for “Mail”. Click the Mail (Microsoft Outlook) result to open the Mail Setup dialog. - Create a New Profile
Click Show Profiles. Click Add, enter a name for the new profile, and click OK. Follow the prompts to add your email account again with the correct SMTP settings. - Set the New Profile as Default
Back in the Mail dialog, select the new profile. Choose the option “Always use this profile” and click Apply, then OK. Open Outlook to test sending email.
If Outlook Still Has Issues After the Main Fix
Error Persists After Correcting SMTP Settings
If the error continues, your internet service provider might be blocking the SMTP port. Contact your ISP to ask if they restrict port 587 or 465. You can also try using your provider’s alternative SMTP port, such as port 25, though this is less common for consumer accounts.
Outlook Works for Receiving But Not Sending
This confirms the issue is isolated to the SMTP server settings. Double-check that you are not using an old password. Some providers require an app-specific password if you have two-factor authentication enabled. Generate this password in your email provider’s security settings and use it in Outlook.
Error Occurs Only on Certain Networks
The problem may be with the network you are using. Corporate or public networks often have strict firewall rules. Try connecting to a different network, like a mobile hotspot, to see if the email sends. If it works, you must contact the network administrator of the problematic network.
SMTP Authentication Methods Compared
| Item | Basic Authentication | Modern Authentication (OAuth 2.0) |
|---|---|---|
| Description | Uses a username and password directly | Uses secure tokens from your provider’s login page |
| Security Level | Lower, if not used with encryption | Higher, tokens are time-limited |
| Provider Support | Common on older or personal servers | Required for Microsoft 365, Gmail, and Outlook.com |
| Setup in Outlook | Enter password in Account Settings | Triggers a web login pop-up from your provider |
You can now send emails again after fixing the SMTP protocol error. Verify your outgoing server authentication is the most reliable first step. For advanced security, ensure your provider supports Modern Authentication. A concrete tip is to always obtain the exact SMTP settings from your email provider’s support website, as defaults can change.