Microsoft Outlook is a powerful email client, but users may occasionally encounter various error codes that disrupt email functionality. This guide outlines some of the most common Outlook error codes, their causes, and step-by-step troubleshooting methods.

1. Error Code: 0x80042108 – Unable to Connect to Incoming (POP3) Mail Server

Cause: Outlook cannot establish a connection to your mail server.

Troubleshooting Steps:

• Check your internet connection.
• Verify that POP/IMAP and SMTP server settings are correct.
• Ensure your email account is properly configured in Outlook.
• Review firewall settings or security software that might be blocking Outlook.
• Temporarily disable third-party antivirus software.

2. Error Code: 0x80042109 – Cannot Connect to Outgoing (SMTP) Mail Server

Cause: Outlook cannot communicate with the SMTP server.

Troubleshooting Steps:

• Confirm your SMTP settings (port and encryption).
• Check firewall or antivirus settings that may block outgoing mail.
• Verify that the email provider’s SMTP server is operational.

3. Error Code: 0x800ccc0e – Connection to Server Was Interrupted

Cause: Loss of connection to the mail server.

Troubleshooting Steps:

• Verify internet connectivity.
• Use webmail to check if the server is down.
• Disable VPN and attempt to reconnect.

4. Error Code: 0x800ccc19 – Server Timed Out

Cause: Outlook times out while connecting to the server.

Troubleshooting Steps:

• Increase server timeout setting in Outlook.
• Reduce attachment sizes.
• Check for provider outages.
• Clear large or stuck emails in the Outbox.

5. Error Code: 0x8004210a – POP Server Timeout

Cause: Server response delay.

Troubleshooting Steps:

• Check POP/IMAP settings.
• Confirm stable internet connection.
• Increase timeout in Outlook.
• Repair Outlook profile.

6. Error Code: 0x80040900 – Server Not Found

Cause: Incorrect server address or DNS issues.

Troubleshooting Steps:

• Verify POP3, IMAP, and SMTP server addresses.
• Check DNS settings.
• Restart Outlook after configuration changes.
• Ensure local server availability.

7. Error Code: 0x80040201 – Unknown Error

Cause: Likely a corrupted Outlook profile.

Troubleshooting Steps:

• Repair or recreate your Outlook profile.
• Disable add-ins temporarily.

8. Error Code: 0x80070057 – Parameter Incorrect

Cause: Account setting or registry issue.

Troubleshooting Steps:

• Validate mail server configurations.
• Create a new profile to replace corrupted ones.
• Reset Outlook registry settings (use caution).
• Use the Microsoft Support and Recovery Assistant.

9. Error Code: 0x8004210b – Connection Interrupted

Cause: Network or server interruptions.

Troubleshooting Steps:

• Confirm internet access.
• Check mail server status.
• Temporarily disable firewall/antivirus.
• Repair Outlook installation.

10. Error Code: 0x80004005 – Unspecified Error

Cause: Could be related to profile corruption, Office installation issues, or file system problems.

Troubleshooting Steps:

• Start Outlook in Safe Mode.
• Repair Office installation.
• Create and switch to a new Outlook profile.

11. Error Code: 550 – Mailbox Unavailable

Cause: The recipient’s mailbox is either full or temporarily unavailable.

Troubleshooting Steps:

• Verify the recipient’s email address.
• Ask the recipient to check their mailbox status.
• Retry sending the email later.

Also, delete all old and junk emails from the server in Outlook.

12. Error Code: 0x8004010f – Operation Failed

Cause: Profile or mailbox access issue.

Troubleshooting Steps:

• Create a new Outlook profile.
• Repair existing profile and check data files (OST/PST).
• Confirm correct server settings.

General Troubleshooting Checklist

1. Check Your Internet Connection

Ensure that your device has a stable and active internet connection.

2. Repair Your Outlook Profile

Navigate to Control Panel > Mail > Show Profiles, then select Repair. Alternatively, create a new profile to resolve corruption.

3. Verify Email Account Settings

Ensure all IMAP/POP3 and SMTP settings are up to date as per your provider’s documentation.

4. Run Microsoft Office Repair

Go to Control Panel > Programs > Programs and Features, select Microsoft Office, then click Repair.

5. Update Outlook

Make sure Outlook is updated to the latest version to benefit from bug fixes and performance improvements.

6. Disable Add-ins

Open Outlook in Safe Mode (hold Ctrl while launching) and disable unnecessary add-ins.

7. Clear Outlook Cache

Clear the cache or recreate the Outlook profile if performance is degraded or errors persist.

8. Use Microsoft Support and Recovery Assistant (SaRA)

Download and run the SaRA tool to diagnose and automatically fix many Outlook-related issues.

If you’re still encountering issues after following the troubleshooting steps, SupportPRO is here to help. Whether it’s Outlook configuration, software errors, or any hosting-related challenge, our 24/7 technical experts can provide hands-on assistance.