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Unable to send Emails on MS Outlook 2007

Catherine Edellstein 0 Reputation points
2026-02-23T15:32:34.5166667+00:00

Unable to send Emails in MS Outlook 2007. Have checked all settings in both Pop3 and Imap. All settings are correct, but still can not send Email. No problem receiving Email. Have emptied all sent and received Emails from the Comcast server and emptied all trash. After all checks and changes we have shut down the computer and we booted. Still all attempts to send Emails have failed. Please advise how to overcome this problem. Thank you

Outlook | Windows | Classic Outlook for Windows | For home
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  1. Kal-D 7,365 Reputation points Microsoft External Staff Moderator
    2026-02-25T17:07:54.56+00:00

    Hi Catherine Edellstein,

    Welcome to Microsoft Q&A.

    If you can receive mail but can’t send from Outlook 2007, the settings may still be “correct” yet sending fails because of modern TLS security requirements:

    • Comcast/Xfinity has required TLS 1.2 and discontinued older TLS (1.0/1.1). Outlook 2007 (especially on older Windows versions) may not support TLS 1.2 by default, so the SMTP session is rejected before the message can be submitted.
    • Outlook 2007 is also out of support (ended October 10, 2017), so compatibility with newer security standards is limited.

    What to try (quick checklist)

    1. In Outlook 2007: Tools > Account Settings > Change > More Settings
      1. Outgoing Server tab: Check "My outgoing server (SMTP) requires authentication" > Select "Use same settings as my incoming mail server"
      2. Advanced tab: SMTP server smtp.comcast.net, port 587 (with "This server requires an encrypted connection (TLS)" checked) or port 465 (SSL)
    2. Check your Xfinity account security:
      • Ensure Third-Party Email Access is allowed for your mailbox.

    If the issue persists

    At that point it’s very likely a TLS compatibility limitation with Outlook 2007/older Windows. The practical workaround is to use Xfinity Webmail or move the account to a newer supported email app/Outlook version.

    For reference: Office 2007 end of support

    Please let me know if this proves useful to you, or if you would like further assistance.

    I'm looking forward to your reply.

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

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  2. Roger Reed 335 Reputation points
    2026-02-24T12:45:02.5733333+00:00

    This usually happens in Microsoft Outlook 2007 when the outgoing server auth isn’t enabled. Go to account settings → outgoing server and check “SMTP requires authentication,” then make sure you’re using port 587 with TLS. That fixes it most of the time 👍

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  3. AI answer

    2026-02-23T15:32:44.03+00:00

    If you are unable to send emails in MS Outlook 2007 while receiving emails is functioning correctly, there are a few steps you can take to troubleshoot the issue:

    1. Check SMTP Settings: Ensure that your SMTP server settings are correct. Sometimes, the outgoing server settings can be misconfigured, which would prevent sending emails.
    2. Enable Authentication: Make sure that your email account is set to authenticate with the outgoing server. You can do this by going to the account settings and ensuring that the option to log on to the incoming server before sending mail is enabled.
    3. Repair Email Account: You can try repairing your email account in Outlook. This can sometimes resolve configuration issues that may be preventing emails from being sent.
    4. Check Send/Receive Groups: If the Send/Receive group is damaged, it may prevent emails from being sent. You can create a new Send/Receive group to see if that resolves the issue. To do this:
      • Go to the Tools menu, point to Send/Receive Settings, and select Define Send/Receive Groups.
      • Create a new group and configure it appropriately.
    5. Check for Errors: If you receive any error messages when trying to send an email, note them down as they can provide clues to the underlying issue.
    6. Firewall/Antivirus Settings: Sometimes, firewall or antivirus software can block outgoing emails. Check to ensure that Outlook is allowed through your firewall and that your antivirus settings are not interfering with email sending.
    7. Update Outlook: Ensure that your Outlook is updated to the latest version available for 2007, as updates can fix bugs and improve functionality.

    If you have gone through these steps and still cannot send emails, consider reaching out to your email service provider for further assistance, as there may be server-side issues affecting your ability to send emails.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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