How To Fix MS Outlook Unable to Successfully Send Email Outgoing Messages

Outlook is one of the most popular email clients used by millions of people worldwide. However, sometimes you may encounter issues where Outlook is unable to send outgoing email messages successfully. This can be frustrating as it prevents you from communicating effectively for work or personal needs.

The good news is, there are several things you can try to troubleshoot and fix this problem on your own. As an IT professional with over 10 years of experience, I will provide you a detailed guide on the various reasons why Outlook may not be sending emails and how to resolve them.

Common Reasons Why Outlook Can’t Send Emails

Here are some of the most common reasons why Outlook might be unable to send outgoing emails:

1. No Internet Connectivity

Outlook requires an active internet connection to be able to send and receive emails. If your internet is down or disconnected, emails will fail to send and remain stuck in the outbox.

Fix: Check your internet connectivity by opening your web browser or another internet-dependent application. If those aren’t working, troubleshoot your internet connection with your ISP or router settings.

2. Incorrect Outgoing Mail Server Settings

If the outgoing mail server settings configured in Outlook are incorrect, it cannot connect to the server to send outgoing emails.

Fix: Go to File > Account Settings > Select your email account > More Settings > Outgoing Server tab. Verify the settings for the SMTP server match what your email provider has specified.

3. Offline Mode Enabled

Outlook has an offline mode that allows you to work without an internet connection. If this gets enabled accidentally, emails will not send.

Fix: Go to the Send/Receive tab > Select Work Offline to disable this mode.

4. Outlook Add-ins Causing Conflicts

Some add-ins like antivirus, security tools, or even third-party Outlook add-ons can end up blocking Outlook from sending emails.

Fix: Launch Outlook in Safe Mode which will disable all add-ins. If emails now send fine, individually enable add-ins one by one to identify the problem application.

5. Outlook Account Access Blocked

If there was suspicious activity detected from your account like multiple failed login attempts, the email provider may have temporarily blocked access to prevent misuse.

Fix: Try logging in to your email account from the provider’s website. If access is blocked, follow their instructions to unblock access before retrying Outlook.

6. Outlook Profile Corruption

In some cases, the Outlook profile which contains your account settings and data files may have become corrupted and prevent sending emails.

Fix: Create a new profile in Outlook by going to File > Info > Add Account > Manually set up the existing account from scratch on the new profile.

Advanced Troubleshooting Tips

If none of the above common fixes resolve your issue, try these advanced troubleshooting tips:

Enable Logging & Check Errors

You can enable logging in Outlook to record activity and errors in detail. This log can then be analyzed to identify potential causes.

To enable logging:

  1. Exit Outlook
  2. Browse to %temp% folder
  3. Rename the Outlook folder to OldOutlook
  4. Launch Outlook so a new log is generated on send failures
  5. Check errors in the new Outlook folder logs after trying to send emails

Look for error codes, failed network calls, or access denied messages that indicate the potential cause.

Repair Office Installation

Corruption in the Office installation or issues after an update could prevent Outlook from working correctly.

Attempt repairing Office by going to Control Panel > Programs > Uninstall a Program > Right-click Office > Change > Online Repair.

Contact Email Provider Support

As a last resort, contact your email provider’s technical support if the above troubleshooting did not resolve the issue.

Provide detailed information on the troubleshooting steps attempted and error messages to help them troubleshoot further based on the server-side configurations and logs.

Preventing Outlook Send Issues

Here are some best practices to avoid Outlook send issues occurring in the first place:

Keep Software Updated

Regularly install the latest Windows and Office updates to fix bugs and ensure maximum compatibility with email providers.

Use Antivirus and Firewalls

Use reputed antivirus software and firewalls to prevent malware or remote attacks from disrupting Outlook processes and communications.

Back Up Outlook Regularly

Schedule regular Outlook data file backups to restore quickly in case the current files get corrupted.

Don’t Click Unsafe Links

Be careful to not click unsafe, unknown links in emails to prevent malware from entering your system and hacking or blocking access.

When to Seek Professional Help

If you have attempted most of the common troubleshooting steps but are still unable to resolve Outlook send issues, it is best to seek assistance from a professional IT consultant or technician:

  • They have advanced tools, knowledge and experience with a variety of unique issues that are difficult to diagnose yourself.
  • Professionals can remotely access your system safely to inspect configurations.
  • They can test sending emails from their own systems to check if the issues lie with your Outlook client or email provider server.
  • If needed, they can migrate your Outlook profile and data to a new system without loss of emails or data.

Investing in professional help can save you a lot of time and frustration trying to fix Outlook problems on your own without success. In most cases, a professional can troubleshoot and resolve Outlook send issues within a few hours or days based on the complexity.


Not being able to send outbound emails is one of the most commonly faced problems by Outlook users. However, as seen above, there are various troubleshooting steps you can try yourself to identify and fix the problem. Getting to the root cause requires patience and a systematic approach.

If basic troubleshooting does not work, enable detailed logging, attempt repairs, or contact provider support for assistance. In complex cases, seeking help from an IT professional can quickly resolve Outlook send issues through advanced diagnostics and data recovery techniques.

Implementing best practices for software updates, security, and backups can also prevent such Outlook problems from occurring so frequently.

I hope this detailed guide gives you a good understanding of the likely reasons why Outlook may not send emails and the troubleshooting methods to try on your own. Let me know if you have any other questions!