How to Fix: Exchange Online User Suddenly Can't Send E-Mails (Stuck in Outbox)

Hi everyone, A user in our tenant reported that outgoing emails are not being sent. When she tries to send via the Outlook Desktop App, the emails remain stuck in the Outbox without any error message. When using OWA, the emails are saved in drafts, and after a while, the error message "Something went wrong, and we haven't been able to send your message yet" appears. This is not a new user, and I’m not aware of any recent

Verify Microsoft Service Health (Exchange Online User suddenly cant send E-Mails)

The workflow begins at a specific Outlook entry point: Open the Outlook Desktop App and click on the Send / Receive tab in the top ribbon

Primary Steps to Clear Stuck Outbox (When Exchange Online User suddenly cant send E-Mails)

This Fix: Exchange Online User Suddenly Can't Send E-Mails procedure uses the controls available in Outlook workspace; complete each action before moving to the next.

1. Open the Outlook Desktop App and click on the Send / Receive tab in the top ribbon
2. Click the Work Offline button. (Expected result: The status bar at the bottom will display "Working Offline" with a red cross, stopping the continuous hidden send loop)
3. Navigate to the Outbox folder in the left navigation pane
4. Click and drag the stuck emails from the Outbox into the Drafts folder
5. Return to the Send / Receive tab and click Work Offline again to reconnect to Exchange Online
6. Look at the bottom right status bar to verify it says Connected to: Microsoft Exchange
7. Once the Service Health dashboard confirms the incident is resolved, open the messages in the Drafts folder and click Send

Alternative Local Troubleshooting (If Exchange Online User suddenly cant send E-Mails Post-Incident)

• Navigate to File > Info > Account Settings > Account Settings .
• Under the Email tab, select the affected Microsoft 365 account and click Repair... .
• Choose Advanced options , check Let me repair my account manually , and follow the wizard to refresh the server connection parameters.
• Restart Outlook to verify if outgoing mail flow is restored.

How to Verify the Outlook Result

The workflow is complete only after this confirmation: Once the Service Health dashboard confirms the incident is resolved, open the messages in the Drafts folder and click Send If the expected state is missing, revisit Click the Work Offline button. (Expected result: The status bar at the in Outlook workspace.

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For local work related to Fix: Exchange Online User Suddenly Can't Send E-Mails, WPS Office is a free Microsoft Office-compatible alternative. It cannot repair a proprietary Outlook service, add-in, account, or Windows/macOS installation state, so use the verified Microsoft procedure above for the original fault.

For the local work surrounding “Fix: Exchange Online User Suddenly Can't Send E-Mails,” WPS Writer and WPS PDF can handle local documents, attachments, PDFs, and reusable message drafts. WPS AI can draft or refine email text and summarize attached document content. The interface is lightweight and familiar to Microsoft Office users, which makes moving routine local work straightforward without changing the Microsoft-side setting discussed here.

Outlook FAQs About Fix: Exchange Online User Suddenly Can't Send E-Mails

Why is there no error message when an Exchange Online User suddenly cant send E-Mails in the Outlook Desktop App?

During backend sync incidents like EX917667, the desktop app repeatedly queues the message to the server. Because the connection isn't explicitly rejected but rather delayed or hung by Microsoft's transport servers, Outlook keeps the item in the Outbox indefinitely without generating a local bounce-back error.

What does "Something went wrong, and we haven't been able to send your message yet" mean in OWA?

This specific Outlook on the Web (OWA) error indicates that the web client successfully saved the email locally to the Drafts folder but timed out when attempting to execute the final send command. This almost always confirms a Microsoft 365 backend service degradation.

Can I use the mobile app if an Exchange Online User suddenly cant send E-Mails?

If the issue is tied to a tenant-wide Microsoft Service Health incident, the Outlook mobile app will typically experience the exact same sending failures. You will need to wait for Microsoft to issue a fix or use alternative communication channels.

How do I force Outlook to send emails after the Exchange service is restored?

Toggle Work Offline on and off under the Send / Receive tab, wait for the connection status to show "Connected," and then press F9 (Send/Receive All Folders) to force a manual sync. If messages are still stuck, manually move them to Drafts, open them, and click Send again.