Messages not sending from New Outlook (Microsoft 365)

Question

Messages not sending from New Outlook (Microsoft 365)

Judith Rhodes 0

So.... I've read that we've all got the same problem - but where is the answer? Is anybody listening/ reading? Why are we all paying for such a deeply sub-standard product?

[And don't get me started on not being able to delete attachments!!!]

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2 answers

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Answer 1

Chloe-V 7,255 Microsoft External Staff Moderator

Hi Judith Rhodes,

Welcome to Microsoft Q&A forum.

To help in the right direction and quickly narrow down why New Outlook (Microsoft 365) can’t send emails, please share the details below:

1. What type of account are you using?

A personal Microsoft account (typically ending ******@outlook.com / @hotmail.com / @live.com), or
A Microsoft 365 work/school account (business/work/school)?

2. What happens when you select Send?

Does the message stay in Outbox or Drafts?
Do you see any prompt/error message or code (even briefly)? If yes, please send the exact text/code via private message.

3. Have you tested sending via Outlook on the web (OWA)?

Once I have these details, I’ll provide the next appropriate troubleshooting steps.

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.

Judith Rhodes 0 Reputation points

2026-03-31T11:07:26.35+00:00

Hello Chloe

I have Microsoft 365 personal. My email account is gmail, set up to synch with Outlook. Until a couple of weeks ago I had the old version of Outlook but it completely stopped synching. My computer person tried with the new version and my account did synch.

I don't much like the new version, it's nowhere near as efficient and effective as the old version. For example not being able to delete attachments and so on. It operates far more like webmail - yet my main reason for using Outlook is that it isn't (or rather wasn't) like Webmail.

Regrading messages not sending - this happens if I've saved the message part way through, or navigated away from Outlook so that it autosaves. I do get a warning message, small and at the top right-hand corner of the screen so it's not at all obvious. It say the message can't be sent at present, try again. Pointless, as trying again achieves nothing. The message saves in draft, so yes I can send from webmail or the app on my phone. But why should I have to?

I note all the suggestions about resolving these issues by going back to Classic Outlook, but that's not a solution for me if it doesn't synch with my gmail. And it's such a misfire to offer a new version that's imperfect, and send users back to the old version!

With thanks,

[Moderator Note: Personal Info Removed]
Chloe-V 7,255 Reputation points Microsoft External Staff Moderator

2026-04-01T00:02:41.8033333+00:00
Hi Judith Rhodes,

Please note that our forum is a public platform, and we will modify your question to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.

I understand how frustrating this can be, especially when core actions such as composing and sending emails are affected.

Please note that this is a user‑to‑user support forum. Moderators and contributors are unable to intervene in Microsoft product features or access back‑end systems. Our role is limited to providing technical guidance based on reported issues, questions, and shared ideas.

As this scenario involves Microsoft 365 Personal used with a Gmail account, the most appropriate next step is to contact Microsoft Support so they can review your case at the account level and, if applicable, record the feedback with the product team.

You can reach Microsoft Support by following these steps:

Go to Contact Us: https://support.microsoft.com/contactus

Select Show expanded list of products

Choose Outlook > Get Home support

In the search box, enter Outlook live chat, then select Get Help > Contact Support

Sign in with the affected account. If you can’t access it, sign in using a different Microsoft account to see available support options

Under Products & Services, select Other Products > Outlook, then choose Chat with a support agent via web browser

Thank you for your understanding.

Answer 2

In New Outlook for Windows there are two separate issues reflected in the context:

Messages not sending / integrations not working
New Outlook is not yet fully MAPI‑compliant. Features that rely on the old MAPI integration (for example, Word mail merge to email or “Send as attachment” directly from Word/Excel/PowerPoint/QuickBooks) either do not work or only partially work. In these cases, the merge or command appears to complete, but no messages are actually sent and nothing shows in Sent Items. The current workaround is to switch back to Classic Outlook, which still supports full MAPI integration and allows these scenarios to work normally. Classic Outlook is also what Windows desktop apps expect when they call the default mail client to send attachments.
Attachment handling differences
New Outlook has different attachment behavior and some attachment operations are handled differently than in Classic Outlook. If attachment actions (including deleting attachments in certain flows) are critical, Classic Outlook currently provides the more complete and predictable experience.

Because New Outlook is still under active development, some features are only partially available. For reliable sending from other apps (mail merge, “share to email,” etc.) and for more mature attachment handling, use Classic Outlook as the default mail client until New Outlook reaches feature parity.

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Messages not sending from New Outlook (Microsoft 365)

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