How to Fix Outlook Not Sending Emails on Windows 10/11

| Updated on February 29, 2024

Summary: If you are facing issues with Microsoft Outlook, such as not being able to send emails on Windows 10 or 11, follow the solutions discussed in this guide to troubleshoot and fix the issue. 

Also, learn an advanced solution to recover and restore mail items from inaccessible, corrupt, or damaged Outlook PST data files (which could be a reason behind the issue) to a new Outlook importable PST format.

In the business world, email is the primary channel for internal and external communication between employees and external parties, with nearly 100% penetration. Therefore, a digital outage can have severe consequences on the business. 

Outlook is one of the most well-known mailing and calendaring apps used by businesses and professionals across the globe. However, some temporary issues with the clients, data files, or the Windows system can lead to issues that can prevent the ongoing flow of messages. 

This article informs of the reasons that can lead to Microsoft Outlook outages and prevent it from sending electronic mail on Windows 10/11. You will also learn the workarounds and solutions to effectively troubleshoot and resolve the errors.

Common Reasons for Outlook Not Sending Emails

Outlook users may face difficulties in sending electronic messages on Windows 10/11 due to several factors, such as:

  • Unstable or unreliable internet connection
  • Wrong recipient address
  • Inconsistent or oversized PST file
  • Wrong or outdated password
  • Incorrect server settings or misconfigured account settings
  • Large or multiple attachments
  • Software conflicts
  • Wrong antivirus or firewall settings
  • Outdated applications 
  • Temporary server-related issues 

If there are connection issues and to avoid similar recurrence, you may need to reorganize the mailbox so that folders contain no more than 5000 items each.

Solutions to Troubleshoot and Resolve Outlook not sending emails on Windows 10/11

Follow the below solutions in the given order to effectively troubleshoot and resolve the Outlook not sending virtual message issue.

1. Check the Basics

Users of this application often make mistakes in typing incorrect addresses and ensuring electronic mail hygiene. Therefore, take care of the following basic issues:

  1. The electronic mail should have the correct address in the To, Cc, and Bcc fields. There should be no special characters or wrong spellings, as that can lead to failure in messaging.
  2. Check Work Offline is not enabled. If enabled, disable it to allow Outlook to send virtual messages. It is easy to search for this option under the Send/Receive tab.
  3. Make sure the online message being sent does not have large attachments or too many attachments.
  4. If the password has been changed recently or expired, reset the password and then provide a new password to Outlook. 

After verifying the basics, try to resend the email. 

2. Check and Fix Network Connection Issues 

Double-check that the internet is working and that there are no firewall conflicts with the application. Follow the below steps to fix network issues:

  • Restart the router and modem, and test the Ethernet cable for proper connection. 
  • Open a web browser and then launch any website. If it loads, the internet is working fine.
  • Then go to the Outlook web app in the web browser and try to sign in. If you can’t log in, wait and try again after some time. It’s possible that the server is under maintenance and may come online after a while. 

Also, check the firewall rules and make sure it is not blocking any ports used by Outlook and the virtual mail service provider.  

The graph below shows the top industries that are using Microsoft Outlook for their business growth. Needless to say, in the digital age, the information and technology sector knows the efficiency of using Outlook services. 

 Distribution of Companies Using Microsoft Outlook by Industry

3. Update Outlook and Windows 10/11 

Updating Outlook and Windows 10/11 can help resolve compatibility issues that can be a reason for mail not being sent. To update the application, follow these steps:

  • Open Outlook and go to File > Office Account > Update Options.
  • You will see an option ‘Update Now.’ Click on it and then wait for the system to test for new updates.
Update Outlook and Windows 10/11 
  • If it shows new upgrades, then follow the update wizard to install and apply all systems.

To update Windows 10/11, follow these steps:

  • Press the Windows key on the keyboard and then click on Settings (gear icon).
    To update Windows
  • Then click Update & Security and click Windows Update.
    click Update & Security and click Windows Update.
  • Click the Check for updates button and, if available, download and install them. 

Once updated, restart the system and then review if Outlook can now send messages in Windows 10/11.

4. Use the Microsoft SaRA Tool 

If you are using a Microsoft 365 or Office 365 email account, utilize the Microsoft Support and Recovery Assistant (SaRA) tool to troubleshoot and resolve issues preventing the system from working in Windows 10/11.  The steps are as follows:

  • Download and run the SaRA tool on a Windows 10/11 PC. The installation is straightforward, just like installing any other software. However, you will need administrator permissions to install and run the SaRA tool.
    SaRA tool
  • After the installation, launch it and then follow the on-screen instructions.
  • Based on your selections, SaRA will scan the system and detect issues that are preventing the message from being sent.
  • The SaRA tool will try to resolve it if it can otherwise provide a solution that can be applied to resolve the issue with the system and allow Outlook to send the virtual message successfully. 

5. Disable and Remove Incompatible or Add-Ins 

Follow the below steps to search and remove the faulty add-in and fix Outlook to ensure uninterrupted message flow. 

  • Close Outlook 
  • Then hold the SHIFT key and double-click on the Outlook icon to launch it in Safe mode. 
  • Then click File > Options > Add-ins.
  • Then search and click on the Go button.
  • Unselect all add-ins and click OK to disable them.
  • Then close Outlook and start it again normally – not in safe mode.
  • Try mailing a new one. If it is sent successfully, activate one add-in at a time and restart Outlook.
  • Send a test message and test if the application can send and deliver the message. 
  • If the message delivery fails after activating one of the add-ins, opt for it and click Remove. This will uninstall and remove from Outlook and fix the issue permanently.


Troubleshooting Outlook’s inability to send emails on Windows 10/11 requires a systematic approach. This includes identifying and addressing the underlying causes that may prevent messages from being sent. 

This article discussed the reasons and solutions to troubleshoot and resolve the Outlook not sending online messages issue and restore its functionality for new ones as well.Remember to use an advanced Outlook PST repair tool, such as Stellar Repair for Outlook, to repair and recover mail items. These include messages, contacts, attachments, etc. from a corrupt or damaged PST file to a new, healthy PST file. After repair, it becomes easier to import your new profile and restore all messages.

Shinely Ainsworth

Shinely is a tech enthusiast with a bachelor of arts degree in English and Creative Writing. Later on, she turned towards technical writing and has been doing it since 2015. From there onwards, she has been consistently writing technical and troubleshooting blogs and articles. Shinely is a writer and editor with 5 years of experience in writing reviews, news, tips, and troubleshooting articles.

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