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Outlook not sending messages

John Taylor 25 Reputation points
2026-01-12T21:42:38.4966667+00:00

I have both classic and new outlook. neither will send messages.

Outlook | Windows | Classic Outlook for Windows | For home
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AI answer

2026-01-12T21:42:47.79+00:00

If Outlook is not sending messages, there could be several reasons for this issue. Here are some common causes and solutions:

  1. Stuck Read Receipt: One common issue is that a read receipt may be stuck in progress, causing Outlook to continuously attempt to resend it. You can check your Outbox for any messages that might not be visible.
  2. Delivery Location Issues: If you are using a POP3 email account, ensure that the default delivery location is set to a valid folder. If it references a nonexistent folder, it can cause sending issues.
  3. Metered Connection Warning: If you are on a metered connection, Outlook may restrict sending and receiving emails. Ensure you are connected to a non-metered network.
  4. Updates and Add-ins: Ensure that you have the latest updates installed for Outlook. Sometimes, outdated software or conflicting add-ins can cause problems with sending emails.
  5. Corrupted Profile or Data Files: If your Outlook profile or data files are corrupted, it may prevent sending emails. You might need to create a new profile or repair your data files.

If these suggestions do not resolve the issue, you may want to consider running the Classic Outlook Advanced Diagnostics troubleshooter to identify and fix the problem.

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  1. Winnie-B 7,945 Reputation points Microsoft External Staff Moderator
    2026-01-13T03:04:10+00:00

    Hello John Taylor

    Thank you for reaching out to Microsoft Q&A Forum. I understand how frustrating this is, you're not being able to send messages from either Classic or New Outlook.

    To help me guide you more precisely, could you please share a bit more information? Such as:

    • Your account type (Outlook.com/Exchange/IMAP/POP/Gmail)?
    • Whether messages are stuck in Outbox or you get an error/bounce (and the exact error message)?

    In the meantime, here are some steps that you could try:

    1. Check if you can send from Outlook on the web

    • Press Ctrl + Shift + Delete to clear cache/cookies
    • Sign in at https://outlook.live.com and try sending a test email there.
    • If it also fails on the web, this points to an account-level restriction.
    • If it works on the web but not in the app, the issue is local to the app/device.

    2. Check your internet connection or try a different network

    • Ensure you have stable internet
    • Use mobile data instead of WiFi, use a different device

    3. Restart Outlook in safe mode

    • Close Outlook completely
    • Press Windows + R, type outlook.exe /safe > press Enter
    • Try sending in Safe Mode

    4. Check mailbox/storage quota

    If your storage is full, Outlook won’t send or receive. Review storage and free space if needed. You can see Mailbox storage limits in Outlook - Microsoft Support

    For more details, you can check this official guide: I can't send or receive messages in Outlook - Microsoft Support

    Thank you for your understanding and please feel free to let me know how it goes.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".    

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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