Outlook Not Sending Emails Fix (Stuck in Outbox?)

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Outlook Not Sending Emails Fix is needed when emails stay in the Outbox, fail to send, or show an error after you click Send.

This issue usually happens because Outlook is offline, your internet connection is unstable, the message has a large attachment, outgoing server settings are incorrect, security software is blocking Outlook, or your Outlook profile needs repair.

Quick Fix

Check your internet connection, then make sure Outlook is not set to Work Offline. If the email is stuck in the Outbox, remove large attachments and try sending the message again.

Try This First

• Email stuck in Outbox → check Outbox and resend it
• Outlook says Working Offline → turn off Work Offline
• Email has large attachment → remove or reduce the attachment
• Send error appears → check account and SMTP settings

If the issue continues, follow the fixes below.

Why Is Outlook Not Sending Emails?

Outlook may fail to send emails when it cannot connect to your email server or when the message cannot be processed correctly.

This can appear as emails stuck in Outbox, send/receive errors, messages failing to deliver, or Outlook showing that it is working offline.

What Causes Outlook Not Sending Emails?

The most common causes include:

• No internet connection
• Outlook set to Work Offline
• Emails stuck in Outbox
• Large attachments
• Incorrect SMTP settings
• Antivirus or firewall blocking outgoing mail
• Corrupted Outlook profile
• Email server problems

This issue usually means Outlook cannot send the message from your computer to your email provider’s outgoing mail server.

How to Fix Outlook Not Sending Emails

Follow these steps until Outlook sends emails normally again.

Check Your Internet Connection

  1. Open a browser such as Chrome or Edge
  2. Try opening a website
  3. If websites do not load, restart your router
  4. Reconnect to WiFi or Ethernet
  5. Open Outlook again
  6. Click Send/Receive
  7. Try sending the email again

If Outlook is not working properly in general, follow this guide: Outlook Not Working Fix

Outlook needs a working internet connection to send messages through your email provider.

Turn Off Work Offline Mode

  1. Open Outlook
  2. Look at the bottom status bar
  3. Check if it says Working Offline
  4. Click the Send/Receive tab at the top
  5. Click Work Offline once to turn it off
  6. Wait a few seconds
  7. Check if the Working Offline message disappears
  8. Try sending the email again

When Work Offline is enabled, Outlook will not connect to the mail server even if your internet is working.

Check the Outbox Folder

  1. Open Outlook
  2. Look at the left folder list
  3. Click Outbox
  4. If you do not see Outbox, expand your mailbox folders or scroll down
  5. Look for emails stuck in the Outbox
  6. Open the stuck email
  7. Check the recipient address, subject, message content, and attachments
  8. Fix anything that looks wrong
  9. Click Send again

If emails are also not arriving in Outlook, follow this guide: Outlook Not Receiving Emails Fix

A stuck Outbox message can block or delay sending until you correct or remove it.

Reduce Email Attachment Size

  1. Open the email stuck in the Outbox
  2. Look for attached files below the subject line
  3. If the file is large, right-click the attachment
  4. Click Remove Attachment
  5. Save the message as a draft if needed
  6. Upload the file to OneDrive, Google Drive, or another cloud service
  7. Paste the sharing link into the email
  8. Try sending again

Large attachments can stop Outlook from sending, especially if your email provider has attachment size limits.

Check Email Account Settings and SMTP

  1. Open Outlook
  2. Click File
  3. Click Account Settings
  4. Click Account Settings again
  5. Select your email account
  6. Click Change or Repair if available
  7. Check that your email address is correct
  8. Check the outgoing mail server, also called SMTP
  9. Click More Settings if available
  10. Open the Outgoing Server tab
  11. Make sure My outgoing server (SMTP) requires authentication is checked if your provider requires it
  12. Save changes and let Outlook test the account
  13. Restart Outlook and try sending again

If Outlook keeps asking for your password while sending mail, follow this guide: Outlook Keeps Asking for Password Fix

SMTP settings control outgoing email. If they are wrong, Outlook may receive emails but fail to send them.

Restart Outlook

  1. Close Outlook completely
  2. Press Ctrl + Shift + Esc
  3. Open Task Manager
  4. Look for Outlook or Outlook.exe
  5. Select it and click End task if it is still running
  6. Open Outlook again
  7. Try sending the email

Restarting Outlook clears temporary app glitches and stuck sending processes.

Repair Outlook or Microsoft Office

  1. Open Control Panel
  2. Click Programs
  3. Click Programs and Features
  4. Select Microsoft Office or Microsoft 365
  5. Click Change
  6. Choose Quick Repair first
  7. Follow the instructions
  8. Restart your computer
  9. Open Outlook and test sending
  10. If Quick Repair does not help, repeat the steps and choose Online Repair

If Outlook also crashes while you are using it, follow this guide: Outlook Keeps Crashing Fix

Repairing Office can fix damaged Outlook files that prevent email sending.

Check Antivirus or Firewall Safely

  1. Check whether your antivirus or firewall recently showed an Outlook warning
  2. Open your security software
  3. Look for Allowed apps, Firewall, or Application control
  4. Make sure Outlook is not blocked
  5. If you are unsure, do not turn off protection permanently
  6. Add Outlook as an allowed app if your security software provides that option
  7. Restart Outlook and test sending again

Security software can sometimes block outgoing mail connections, but protection should not be left disabled. Use allow-list settings instead of turning security off for long periods.

Create a New Outlook Profile

  1. Close Outlook completely
  2. Open Control Panel
  3. Search for Mail
  4. Open Mail (Microsoft Outlook)
  5. Click Show Profiles
  6. Click Add
  7. Type a new profile name
  8. Add your email account
  9. Choose Prompt for a profile to be used if you want to test it first
  10. Open Outlook with the new profile
  11. Try sending an email

If Outlook gets stuck loading your profile, follow this guide: Outlook Stuck on Loading Profile Fix

A new profile can fix sending problems caused by corrupted Outlook profile data.

Check If the Email Server Is Down

  1. Open your email provider’s webmail page in a browser
  2. Sign in to the same email account
  3. Try sending a test email from webmail
  4. If webmail also cannot send, the issue may be with the email provider
  5. Wait and try again later
  6. Contact your email provider if the issue continues

If webmail can send but Outlook cannot, the problem is likely in Outlook settings, profile, add-ins, or local software.

How to Prevent Outlook Sending Problems

• Keep Outlook and Microsoft Office updated
• Avoid sending very large attachments directly
• Keep your internet connection stable
• Check Work Offline mode if emails stop sending
• Keep account settings and passwords updated
• Repair Outlook when repeated sending errors appear

Frequently Asked Questions

Why are my Outlook emails stuck in Outbox?

Outlook emails usually get stuck in Outbox because of internet problems, Work Offline mode, large attachments, incorrect SMTP settings, or a stuck Outlook process.

Why can Outlook receive emails but not send?

This often happens when incoming mail settings work, but outgoing SMTP settings, authentication, firewall rules, or server settings are incorrect.

Can I fix Outlook sending issues myself?

Yes, most Outlook sending problems can be fixed by checking internet, turning off Work Offline, clearing stuck Outbox messages, reducing attachments, checking SMTP settings, or repairing Office.

You may also want to check our guides on Outlook Search Not Working Fix, Outlook Not Syncing Emails Fix and Outlook Not Opening Fix for related Outlook issues.