cannot send emails

Question

We can receive emails but not send them.

Answer 1

Hi Bruce Derrick

Thank you for reaching out to the Microsoft Q&A forum and for sharing your issue.

To better understand the issue, could you please help confirm a few details:

• Does the issue also occur in Outlook on the web?
• Are you unable to send emails to all recipients or only specific ones?
• Do you see any error message when trying to send an email? If yes, please share the exact error message or a screenshot via private message to avoid exposing any personal or organizational information.
• What type of account are you using (for example: Exchange, POP, or IMAP)?

I look forward to your update.

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Answer 2

Use the following checks in classic Outlook for Windows when messages can be received but not sent:

1. Verify account password
   • If the account password was recently changed on the mail provider’s website, update it in classic Outlook as well. See guidance under Have you changed your password recently? in the Outlook article and follow the steps in Reset a forgotten Microsoft account password if needed.
2. Check for SMTP or relay errors
   • If errors such as 550, 553, or “relay prohibited” appear when sending, this usually indicates a problem with the outgoing (SMTP) server configuration or anti-spoofing protections.
   • Ensure the From/reply address domain matches what the ISP or mail server expects (for example, do not send as ******@contoso.com when connected through an ISP that only allows @proseware.com). If the server enforces this, the return address must use the allowed domain.
3. Check antivirus email scanning
   • Some antivirus products block sending after detecting a virus. Contact the antivirus vendor’s help desk or temporarily disable email scanning (not the entire antivirus) to test, if that is supported by the product.
4. Repair Outlook and the mail profile
   • If send/receive is broken in Outlook itself (buttons not working or messages stuck), run a repair of Office, then repair or recreate the Outlook profile:
     • Use Repair an Office application to fix the Outlook installation.
     • If issues persist, follow Fix your Outlook email connection by repairing your profile or Create an Outlook profile to create a new profile and re-add the account.
5. Start Outlook in Safe Mode
   • Some add-ins can block sending.
   • Start Outlook in Safe Mode by pressing the Windows key, typing outlook.exe /safe, and pressing Enter.
   • If sending works in Safe Mode, disable or remove problematic add-ins and/or create a new profile as described above.

If, instead, the issue is with SQL Server Database Mail or SSRS email delivery (for example, alerts or reports not sending), use the Database Mail troubleshooting steps:

1. Check sysmail_event_log
   • Look for SMTP-related errors such as failure to contact the SMTP server, authentication failures, or the SMTP server refusing messages.
2. Check sysmail_unsentitems, sysmail_sentitems, and sysmail_faileditems
   • sysmail_unsentitems: shows messages with status unsent or retrying (stuck in the queue or waiting to be sent).
   • sysmail_sentitems: confirms which messages were sent and when.
   • sysmail_faileditems: lists messages that failed to send and can be correlated with sysmail_event_log using mailitem_id.
3. Verify SMTP relay/authentication
   • For Database Mail accounts, ensure SMTP authentication (Anonymous, Basic, or Windows) matches the relay server’s requirements on the configured port. A successful TCP connection alone does not guarantee that authentication and TLS settings are correct.
4. For SSRS after TLS hardening (Sweet32 remediation)
   • If SSRS subscriptions stopped sending after disabling weak ciphers, check ReportServerService*.log for TLS/SSL/STARTTLS or authentication errors. These indicate TLS handshake failures with the SMTP server and must be resolved on the SMTP/TLS configuration side.

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References:

• I can't send or receive messages in Outlook
• I receive a 550, 553, or relay-prohibited error when sending email messages
• Troubleshoot Database Mail issues
• Database replication alerts using the SMTP relay Port 25 - Microsoft Q&A
• Birthday attacks against Transport Layer Security (TLS) ciphers with 64bit block size Vulnerability (Sweet32) - Microsoft Q&A
• Databasemail stops working on SQL Server 2025 after CU1 install - Microsoft Q&A
• Mail Merge Emails not sent - Microsoft Q&A
• Class outlook is not working properly after Windows 11 version 25H2 update - Microsoft Q&A
• Can't send or receive email in Outlook.com