Using New Outlook on Windows for professional communication and productivity
Regarding your issue, may I kindly ask a few questions to help understand it better.
- I saw that you posted your question under Business category so to better support you, would you mind letting me know is this account a personal Microsoft account (e.g., account.microsoft.com) or a work/school account (e.g., myaccount.microsoft.com) provided by an organization?
- Are the messages stuck in your Outbox showing as "Queued," or are they going somewhere else like Drafts?
- Do you see any error message when it fails to send? Could you provide a screenshot of it if possible?
- Does this happen when sending to internal recipients (within your organization), external recipients (outside your organization), or both?
- Does this happen with all emails, or only certain recipients or emails with attachments?
- Can you try sending from Outlook on the web and let me know if the same thing happens?
- Does the same issue occur on another device or on a different network (for example, home vs. office)?
Hope to hear back 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.