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Issue sending/receiving emails to external domains

Ayyoub 0 Reputation points
2026-06-10T08:41:39.4433333+00:00

Hello,

For the past week, I have been experiencing an issue with my email account: I am unable to send or receive emails to/from external domains (for example, @gmail.com). Communication within Outlook domains seems to be working correctly.

Could you please assist me in resolving this issue?

Thank you in advance for your help.

Ayyoub

Outlook | Windows | Classic Outlook for Windows | For business

2 answers

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  1. Vergil-V 14,110 Reputation points Microsoft External Staff Moderator
    2026-06-10T09:19:08.9733333+00:00

    Hi Ayyoub

    I understand how concerning it can be when you are unable to send or receive emails with external domains, especially when this affects your daily communication.  

    To better understand your situation, could you please help clarify the following points: 

    1/ Does the same behavior occur when you use Outlook on the web via https://outlook.cloud.microsoft/mail/? 

    2/ When you send emails to external recipients, do you receive any bounce-back message or NDR?  If yes, I would appreciate it if you could share the details through a private message. 

    Please check your inbox for an email with the subject New private message on Microsoft Q&A question to review my response, and look for View message in the banner above the post to access the private message chat.   

     User's image

    3/ When did this situation begin? Did it start recently, or were emails sent successfully before without any issue? 

    In the meantime, you may consider reaching out to your IT administrator within your organization, as they have the appropriate permissions to investigate this further, which is beyond the scope of support available through moderator forums such as mine, including: 

    • Reviewing SPF, DKIM, and DMARC configurations, as these are commonly required by external email providers. 
    • Running a message trace to confirm whether your emails were delivered successfully or if they were blocked during transit. 

    If I’ve misunderstood any part of your situation, or if you have further questions or updates, please don’t hesitate to reply. 

    Thank you for your time, and I look forward to hearing from you soon. 

    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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  2. AI answer

    2026-06-10T08:41:57.8766667+00:00

    Use the following steps to isolate and fix the issue in classic Outlook for Windows when mail only works to internal/Outlook domains but not to external ones:

    1. Confirm basic connectivity
      • In Windows, open a browser and verify that external sites such as http://www.microsoft.com or http://www.bing.com load correctly.
      • If they do not, fix the network first as described in Fix network connection issues in Windows.
    2. Check for sync/send/receive issues in Outlook
      • In classic Outlook, go to the View tab and select the Sync button to force a manual send/receive.
      • Watch the status bar for errors or stalled sync. If messages stay in Outbox or errors appear, continue with the next steps.
    3. Verify password and account authentication
      • If the account password was changed recently on the provider’s website or in Microsoft 365, it must also be updated in Outlook.
      • Follow the guidance under Have you changed your password recently? in the Outlook article to ensure Outlook is using the correct password and, if required, an app password for certain providers.
    4. Run Microsoft Support and Recovery Assistant
      • Use the Microsoft Support and Recovery Assistant (SaRA) to automatically diagnose “Can’t send or receive email in Outlook” issues.
      • This tool checks connectivity, configuration, and common profile issues and can repair them where possible.
    5. Repair Outlook and the Outlook profile
    6. Check for add‑in or local data issues
      • Start Outlook in safe mode (outlook.exe /safe) to disable add-ins. If external mail works in safe mode, an add-in is likely causing the problem; disable or remove problematic add-ins.
      • If there are errors related to data files (.pst/.ost), run the Inbox Repair Tool as described in Repair Outlook data files (.pst and .ost).
    7. Check antivirus and firewall
      • Some antivirus products scan email and can block sending/receiving. Temporarily disable email scanning in the antivirus (or consult the antivirus help desk) and test again.
      • If using a corporate network, the firewall or mail gateway may be blocking external SMTP/Exchange traffic; contact the network or email administrator to verify that outbound and inbound mail to external domains is allowed and that no new restrictions were applied.
    8. If still failing only for external domains
      • Because internal mail works, the issue may be on the server side (Exchange/tenant configuration, transport rules, or external routing). In that case, escalate to the organization’s Exchange/Microsoft 365 administrator to review server logs, connectors, and any transport rules that might block external recipients.

    References:

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