cannot send emails

Hi @Shawnmcallenmri,

Welcome to the Microsoft Q&A forum, and thank you very much for reaching out to us.

Correct me if I’m wrong, but based on your description, it seems you’re able to receive emails without issue, but you're currently unable to send emails even though your mailbox has sufficient storage available (only 4 GB used out of 49.5 GB). I understand how disruptive this can be, especially when it affects your ability to communicate effectively.

Please note that as a Microsoft Q&A moderator, I don’t have access to your specific setup or environment. However, rest assured that I’m committed to helping you as much as I can through research, guidance, and available resources.

To assist you further, could you please clarify the following:

• When attempting to send an email, do you encounter any error messages or notifications? If so, a screenshot would be helpful (please ensure no personal information is visible).
• Which version of Outlook are you using? Is it Classic Outlook, New Outlook, or Outlook on the Web?
• Does the issue occur across different devices, or is it isolated to one device only?
• Are other users experiencing the same issue, or is it specific to your account?

To help identify the root cause of the issue, you (or your administrator) can run a Message Trace in the Exchange Online Admin Center. This tool tracks the status of sent emails and provides detailed insights into whether the message was successfully delivered or if any errors occurred.

For more information, you can refer to this Microsoft Article here.

For workarounds, here are several steps you can try to restore Outlook sending function:

• Try Sending from Outlook Web:
  • Kindly go to Outlook Web and send a test email to yourself or someone in your organization. This helps determine whether the issue is local to your desktop app or account wide.
• Create a New Outlook Profile:
  • A new profile can help rule out issues tied to corrupted settings or misconfigured accounts.
• Check Mailbox Rules:
  • you can check and temporarily disable any mailbox rules such as auto-forwarding or auto-reply rules. As these rules might be interfering with outgoing mail.
• Check Mail Flow Rules in Exchange Online Admin Center:
  • If you're an admin or can reach out to one, you can go to Exchange Online Admin Center > Mail flow > Rules and check on any rules that could be blocking or redirecting outbound messages.

If you experience any issues while following the suggestions I’ve provided, have additional questions, or need further clarification, please feel free to let me know in the comment section below. I would love to assist you further.

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