Emails Not Sending? Here's Your Solution to Outlook Error 0x80042109!

An Outlook error code 0x80042109 means that Outlook is unable to connect to the user's outgoing (SMTP) email server and your recipient will not receive your message. It may be due to some issues with the internet connection, or due to unresponsive Outlook.

When does Outlook error 0x80042109 appear?

Outlook error 0x80042109 typically appears when you attempt to send an email through Microsoft Outlook or synchronize your mailbox with an external email server. The error message displayed on the screen is: "Sending reported error (0x80042109): Outlook is unable to connect to your outgoing (SMTP) e-mail server. If you continue to receive this message, contact the server administrator or Internet service provider (ISP)."

This error doesn't affect the operation of any programs or system processes on your computer. To fix it easily, you need to find its concrete reasons and apply the solutions covered in this article.

The reasons behind Outlook error 0x80042109

1. Incorrect SMTP server settings. One of the primary reasons for this error is misconfigured SMTP server settings in your email account. If the outgoing mail server's address, port number, or authentication method is incorrect, Outlook may fail to connect to the server and display error 0x80042109.
2. Firewall or antivirus blocking the connection. Security software can sometimes block Outlook's connection to the SMTP server. These security measures may mistakenly identify the connection as a security threat and prevent emails from being sent, resulting in Outlook error 0x80042109.
3. ISP restrictions. Some Internet Service Providers (ISPs) may impose restrictions on the use of third-party SMTP servers to prevent spamming. In such cases, users may face the 0x80042109 error while using an SMTP server other than the one provided by their ISP.
4. Damaged Outlook profile. A common cause of the 0x80042109 error is a corrupted Outlook profile. This can happen due to an accidental system shutdown or other issues.
5. Network connectivity issues. Occasional network connectivity issues or unstable internet connections can also cause Outlook error 0x80042109.
6. Email server downtime or issues. Sometimes, the error 0x80042109 may be caused by temporary issues or downtime on the email server itself. In such cases, users may experience difficulties connecting to the SMTP server, which results in the error.
7. Disabled access for less secure apps or enabled 2-Step-Verification. A mail server may restrict third-party applications, such as Outlook, from accessing your mailbox. Using 2-step verification may have the same result.
8. Large email attachments. Sending emails with large attachments can sometimes cause Outlook error 0x80042109. Email servers may have size limits for attachments, and exceeding these limits might lead to connection issues with the SMTP server.
9. Outdated device drivers. Outdated or incompatible device drivers, particularly network drivers, can cause connection issues between Outlook and the SMTP server. Ensuring that all device drivers, especially network-related drivers, are up-to-date can help in preventing error 0x80042109.
10. VPN turned on. Users may encounter the 0x80042109 error when sending messages from Outlook with VPN connected. Try sending email without VPN to see if this is the cause.
11. Incorrect system time and date. An incorrect system time and date can interfere with Outlook's ability to establish a secure connection with the SMTP server, leading to Outlook error 0x80042109.

How to clear Outlook sending error

Waiting for the server to resume normal functioning or contacting the email service provider for assistance might help resolve the issue. Alternatively, you can follow these steps to troubleshoot Outlook error 0x80042109:

• Verify SMTP server settings:
  1. Open Outlook and go to File > Account Settings > Account Settings.
  2. Select the email account that is causing the error and click Change.
  3. Check the Outgoing mail server (SMTP) settings to ensure that they match the data provided by your email service provider.
  4. Click on More Settings > Outgoing Server tab, and make sure the authentication settings are correct.
  5. Go to the Advanced tab and verify the correct port numbers are being used for the SMTP server (usually 465 for SSL or 587 for TLS).
  6. Click OK and then Next to test the settings. If successful, click Finish.
• Use the correct ISP SMTP server:
  1. Contact your Internet Service Provider to obtain the correct SMTP server settings.
  2. Follow the steps in the previous paragraph to update the SMTP server settings in your email account.
• Disable or adjust firewall/antivirus settings:
  1. Open your firewall or antivirus software settings.
  2. Temporarily disable the software or create an exception for Outlook.
  3. Restart Outlook and check if the error persists. If resolved, consider adjusting the firewall/antivirus settings for a long-term solution.
• Troubleshoot network connectivity issues:
  1. Restart your modem/router and computer.
  2. Check for any known network issues with your ISP.
  3. Temporarily disable VPN or proxy services, if in use.
• Reduce email attachment size:
  An advanced automated tool helps compress large attachments before sending. It accurately packs attachments in messages and other Outlook items to ZIP archives. You can use flexible filters and compress each attachment into a separate ZIP file or create a single ZIP archive with multiple attached files. The Unpack Attachments utility can uncompress attached ZIP archives in-place when needed.


• Update device drivers:
  1. Open "Device Manager" and expand the Network adapters section.
  2. Right-click on the network adapter and choose Update driver.
  3. Follow the on-screen instructions to update the driver, and restart your computer.
• Correct system time and date:
  1. Right-click on the system clock in the taskbar and choose Adjust date/time.
  2. Make sure the time and date are set correctly, and the correct time zone is selected.
  3. Click OK and restart Outlook.
• Re-сreate Outlook profile:
  1. From the Outlook File menu, select Account Settings > Manage profiles.
  2. Click Show Profiles, then click Add and enter a Profile Name.
  3. Follow the instructions to set up the profile, and then set it as your default profile.
  4. Restart Outlook, select the created profile, and check to see if the error is fixed.
  
  
• Enable less secure app access or set an app password:
  1. To turn on less secure app access, allow it in your web-based email client settings.
  2. If you are using 2-step verification, set an application password for Outlook in your webmail settings.
  3. Verify that the error is resolved.

Conclusion

Outlook error 0x80042109 occurs when users face issues connecting to their outgoing (SMTP) email server. This error can result from various causes, such as incorrect SMTP settings, firewall restrictions, or large Outlook attachments. Special add-ins and manual methods described in this article can help you fix the problem quickly and easily and minimize the chances of encountering this error in the future.

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About Author

David Godfrin is a software developer and blogger for Outlook and Exchange. He has a strong background in IT and works in the field of software development and tech support since 2011.