Fix Outlook not sending emails in Windows 11

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Why isn’t Outlook sending my emails immediately in Windows 11?

You’re working on an important project deadline when you notice your Outlook emails aren’t leaving your outbox. This common Windows 11 issue affects both personal and business users, creating delays in communication. Whether you’re using Gmail, Exchange, or other email providers, understanding the root causes and solutions will restore your email functionality quickly.

Common causes for Outlook email delivery issues

Outlook email sending issues in Windows 11 often arise from network connection problems, incorrect account settings, or software conflicts. These problems can affect both sending and receiving capabilities, though sometimes only outbound messages are impacted. In many cases, you may still receive emails normally while being unable to send messages—usually due to mismatched configurations between incoming (IMAP/Exchange) and outgoing (SMTP) servers.

This walkthrough outlines a structured approach to diagnosing and fixing Outlook sending problems across major email providers, including Gmail, Exchange, and IMAP accounts. You’ll learn how to test connectivity, verify account configurations, and adjust Windows 11–specific settings that frequently cause delivery failures. To complete the steps, ensure you have administrative access to your computer and know your email login credentials. These methods apply to Outlook 2019, Outlook 2021, and Microsoft 365 versions running on Windows 11, whether installed as standalone applications or as part of a Microsoft 365 subscription.

Resolve Outlook not sending emails today

Verify your internet connection and Outlook online status

  • Check your internet connectivity by opening a web browser and navigating to any website to confirm your connection is stable and functioning properly.
  • Launch Outlook and look at the bottom-right corner of the window where the connection status appears, ensuring it shows “Connected” rather than “Disconnected” or “Working Offline.”
  • If Outlook shows offline status, click the “Send/Receive” tab in the ribbon menu, then click “Work Offline” to toggle your connection back to online mode.
  • Test your connection by clicking “Send/Receive All Folders” in the Send/Receive tab to force Outlook to attempt connecting to your email servers immediately.
  • Restart your router and modem if connectivity issues persist, waiting thirty seconds between turning off and restarting each device to ensure proper network reset.

Check and clear your Outlook outbox for stuck messages

  • Navigate to your Outbox folder in the left sidebar of Outlook to see if any emails are stuck there waiting to be sent to recipients.
  • Double-click any messages in the Outbox to open them, then check for large attachments that might be causing sending delays or failures due to size restrictions.
  • Delete any problematic messages with oversized attachments or corrupted content that might be blocking other emails from sending through your account successfully.
  • Right-click on stuck messages and select “Delete” if they appear corrupted, then try recreating and sending the message again with smaller attachments if necessary.

Expert Tip: Large attachments over 25MB often cause sending failures. Use cloud storage links instead of direct attachments for large files.

Verify and update your email account settings in Windows 11

  • Open Outlook and click “File” in the top menu, then select “Account Settings” and choose “Account Settings” again from the dropdown menu options.
  • Select your problematic email account from the list and click “Change” to access the detailed configuration settings for your specific email provider account.
  • Verify that your outgoing mail server (SMTP) settings match your email provider’s requirements, including server address, port number, and encryption method specifications.
  • For Gmail accounts, ensure the SMTP server is set to “smtp.gmail.com” with port 587 and TLS encryption enabled for proper authentication and message delivery.
  • Click “More Settings” button, then navigate to the “Outgoing Server” tab and check “My outgoing server (SMTP) requires authentication” if it’s not already selected.
  • Test your account settings by clicking “Test Account Settings” button to verify that both incoming and outgoing server connections are working correctly with your current configuration.

Configure Windows 11 firewall and antivirus exceptions for Outlook

  • Press Windows key + R to open the Run dialog, type “firewall.cpl” and press Enter to access Windows Defender Firewall settings directly.
  • Click “Allow an app or feature through Windows Defender Firewall” on the left sidebar to access the application permissions configuration panel.
  • Scroll through the list to find “Microsoft Outlook” and ensure both “Private” and “Public” network checkboxes are marked to allow email communication.
  • If Outlook isn’t listed, click “Change Settings” then “Allow another app” to browse and add your Outlook executable file to the firewall exceptions list.
  • Open your antivirus software settings and add Outlook to the email protection exceptions list, as some security programs block outgoing email connections by default.
  • Temporarily disable your antivirus email scanning feature to test if it’s interfering with Outlook’s ability to send messages through your configured email servers.

Reset Outlook profile and rebuild email account configuration

  • Close Outlook completely and press Windows key + R, then type “appwiz.cpl” and press Enter to open the Programs and Features control panel.
  • Click “Microsoft Office” or “Microsoft 365” in the program list, then click “Change” and select “Quick Repair” to fix common Outlook configuration issues.
  • If Quick Repair doesn’t resolve the issue, run “Online Repair” which requires an internet connection but performs more comprehensive fixes to your Office installation.
  • Create a new Outlook profile by pressing Windows key + R, typing “control mlcfg32.cpl” and pressing Enter to open the Mail Setup dialog box.
  • Click “Show Profiles” then “Add” to create a new profile, following the setup wizard to reconfigure your email accounts with fresh settings and authentication.
  • Set the new profile as default and test sending emails to verify that the fresh configuration resolves your previous sending issues completely.

Troubleshooting Outlook email sending problems in Windows 11

Outlook receives emails but won’t send messages to recipients

  • Check if your email provider requires app-specific passwords for third-party email clients like Outlook, especially for Gmail and Yahoo accounts with two-factor authentication enabled.
  • Generate an app-specific password through your email provider’s security settings and replace your regular password with this specialized authentication code in Outlook’s account configuration.
  • Verify that your email account hasn’t exceeded sending limits imposed by your provider, as many services restrict the number of emails sent per day or hour.
  • Contact your internet service provider to confirm they’re not blocking outgoing email ports, as some ISPs block port 25 to prevent spam distribution from residential connections.

Outlook not sending emails immediately after Windows 11 updates

  • Check Windows Update history to identify recent system updates that might have affected Outlook’s functionality or changed security settings that impact email sending capabilities.
  • Run Windows Update troubleshooter by going to Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update to identify and fix update-related issues automatically.
  • Reset Windows 11 network settings by opening Settings > Network & Internet > Status > Network reset to clear any corrupted network configurations affecting email connectivity.
  • Reinstall the latest Windows 11 cumulative update if email problems started immediately after a recent system update, as this can resolve compatibility issues with Office applications.

Gmail and other provider-specific sending issues in Outlook

  • Enable “Less secure app access” in your Gmail security settings if using older authentication methods, though Google recommends using OAuth2 authentication for better security instead.
  • Configure OAuth2 authentication for Gmail accounts by removing and re-adding your account in Outlook, allowing modern authentication protocols that provide better security and reliability.
  • Check your email provider’s server status page to confirm their SMTP servers are operational, as temporary outages can prevent message sending while receiving continues normally.
  • Verify that your email account hasn’t been temporarily suspended or flagged for suspicious activity by logging into your provider’s web interface to check account status.

Windows 11 compatibility issues affecting Outlook email functionality

  • Update Outlook to the latest version through Microsoft Update or Office Update to ensure compatibility with Windows 11 security features and networking protocols.
  • Run Outlook in compatibility mode by right-clicking the Outlook shortcut, selecting Properties > Compatibility tab, and choosing an earlier Windows version if persistent issues continue.
  • Check if Windows 11’s enhanced security features are blocking Outlook by temporarily disabling Windows Security’s real-time protection to test email sending functionality.
  • Reset Windows 11’s network adapter by opening Device Manager, expanding Network adapters, right-clicking your network device, and selecting “Uninstall device” then restarting your computer for automatic reinstallation.