Microsoft Outlook is a widely-used email client known for its reliability and robust features. However, users occasionally encounter errors that can disrupt their email communication. One such issue is the Outlook error 0x80042109, which prevents users from sending emails. This comprehensive guide will explore the causes of this error, provide troubleshooting steps, and offer advanced solutions to ensure your Outlook runs smoothly.
Understanding Outlook Error 0x80042109

Error 0x80042109 occurs when Outlook fails to establish a connection with the outgoing SMTP (Simple Mail Transfer Protocol) server. This error specifically impacts the email sending functionality, while other Outlook features, such as receiving emails or accessing calendars, remain unaffected.
When users attempt to send an email, they may encounter an error message stating:
“Outlook cannot connect to your outgoing (SMTP) e-mail server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).”
This error can be frustrating, especially for users who rely on timely email communication for personal or professional purposes. It’s important to note that while this error prevents sending emails, you may still be able to receive emails, although other issues can affect incoming mail as well.
Common Causes of Error 0x80042109
Several factors can contribute to the occurrence of error 0x80042109:
- Incorrect SMTP Server Settings: Misconfigured server addresses, port numbers, or authentication settings can prevent Outlook from connecting to the SMTP server.
- Network Connectivity Issues: Unstable internet connections or network problems can disrupt communication between Outlook and the email server. This can sometimes lead to Outlook appearing disconnected.
- Antivirus and Firewall Interference: Overzealous security software may incorrectly flag Outlook’s connection attempts as suspicious and block them.
- ISP Restrictions: Some Internet Service Providers (ISPs) block certain SMTP ports to prevent spam, which can inadvertently affect legitimate email sending.
- Corrupted Outlook Profiles or PST Files: Damaged profile information or Personal Storage Table (PST) files can lead to various Outlook errors, including 0x80042109. In some cases, Outlook may not be able to find the PST file, causing additional issues.
Understanding these causes is crucial for effective troubleshooting and resolution of the error.
Basic Troubleshooting Steps
Before diving into advanced solutions, try these basic troubleshooting steps to resolve error 0x80042109:
1. Verify Internet Connectivity
Ensure that your device has a stable internet connection. Try accessing websites or using other online services to confirm internet availability. If you’re experiencing connectivity issues, restart your modem and router.
2. Check and Update SMTP Settings
Incorrect SMTP settings are a common cause of this error. To verify and update your settings:


- Open Outlook and go to File > Account Settings > Account Settings.
- Select your email account and click “Change.”
- Verify that the outgoing mail server (SMTP) address is correct.
- Click “More Settings” and go to the “Outgoing Server” tab.
- Ensure “My outgoing server (SMTP) requires authentication” is checked.
- In the “Advanced” tab, confirm that the SMTP port is set to 587 (for TLS) or 465 (for SSL).
3. Temporarily Disable Antivirus and Firewall
Security software can sometimes interfere with Outlook’s functionality. Temporarily disable your antivirus and firewall, then attempt to send an email. If successful, you’ll need to configure your security software to allow Outlook’s connections.
4. Restart Outlook and Your Computer
Sometimes, a simple restart can resolve connectivity issues. Close Outlook, restart your computer, and then try sending an email again.
Advanced Solutions for Error 0x80042109
If the basic troubleshooting steps don’t resolve the issue, try these advanced solutions:
1. Change the Outgoing SMTP Port
Some ISPs block the default SMTP port 25. Try changing the port to an alternative:

- Go to File > Account Settings > Account Settings.
- Select your account and click “Change.”
- Click “More Settings” > “Advanced” tab.
- Change the outgoing server (SMTP) port to 587 or 465.
- Click “OK” and try sending an email.
2. Remove and Re-add Your Email Account
Removing and re-adding your email account can help resolve configuration issues:
- Go to File > Account Settings > Account Settings.
- Select your account and click “Remove.”
- Restart Outlook and go to File > Add Account.
- Follow the prompts to re-add your email account.
3. Repair or Reinstall Outlook
If the error persists, consider repairing or reinstalling Outlook:
- Open Control Panel > Programs and Features.
- Find Microsoft Office in the list.
- Right-click and select “Change.”
- Choose “Repair” and follow the prompts.
If repair doesn’t work, uninstall and reinstall Outlook. This process can also help resolve other Outlook errors, such as error 0x8004060c.
4. Use Safe Mode to Identify Problematic Add-ins
Add-ins can sometimes cause connectivity issues. Start Outlook in Safe Mode to disable all add-ins:

- Press Win + R, type “outlook.exe /safe” and press Enter.
- If Outlook works in Safe Mode, go to File > Options > Add-Ins.
- Select “COM Add-ins” and click “Go.”
- Uncheck all add-ins, click “OK,” and restart Outlook normally.
- Re-enable add-ins one by one to identify the problematic one.
5. Utilize Outlook Repair Tools
If you suspect corrupted PST files, use Microsoft’s Inbox Repair Tool (scanpst.exe) or third-party Outlook repair tools to fix data file issues. These tools can also be helpful for resolving errors like 0x800408fc or 0x800ccc67.

Preventive Measures
To minimize the occurrence of error 0x80042109 and other Outlook issues:
- Keep Software Updated: Regularly update Outlook, Windows, and your antivirus software.
- Configure Security Software Properly: Ensure your antivirus and firewall are configured to allow Outlook’s connections.
- Back Up Outlook Data: Regularly back up your PST files and Outlook profiles.
- Monitor Internet Stability: Address any persistent internet connectivity issues with your ISP.
Frequently Asked Questions
- Q: Will error 0x80042109 affect my ability to receive emails? A: No, this error specifically affects sending emails. You should still be able to receive messages.
- Q: Can using a VPN cause this error? A: Yes, VPNs can sometimes interfere with SMTP connections. Try disabling your VPN to see if it resolves the issue.
- Q: How often should I update my Outlook settings? A: It’s a good practice to review your settings whenever you change internet providers or if your email service provider notifies you of any changes.
- Q: Is it safe to use third-party Outlook repair tools? A: While many reputable tools exist, always research and choose tools from trusted sources. Microsoft’s built-in repair tools should be your first choice.
- Q: Can this error be caused by server-side issues? A: Yes, sometimes the problem may be with your email service provider’s servers. If the error persists after trying all solutions, contact your provider’s support team.
Conclusion
Outlook error 0x80042109 can be a frustrating obstacle to email communication, but with the right approach, it’s often resolvable. By following the troubleshooting steps and solutions outlined in this guide, you can overcome this error and ensure smooth email functionality. Remember to keep your software updated, maintain proper configurations, and regularly back up your Outlook data to prevent future issues.
If you continue to experience problems with sending emails, it’s worth checking if the issue is specific to Outlook or if it affects other email clients as well. For instance, if you’re also having trouble sending emails from Gmail, the problem might be related to your email account or internet connection rather than Outlook itself.
Don’t hesitate to seek assistance from Microsoft support or your email service provider if you’ve tried all these solutions and still can’t resolve the error. They can provide more specific guidance based on your email configuration and system setup.