Send & Receive Issues

How to Fix Outlook Receiving Emails but Unable to Send Messages

Huma Ashraf Ch Oct 10, 2026 869 views

Question details

The user is experiencing an issue where Outlook successfully receives incoming emails but fails to send outgoing messages.

How to Fix Outlook Receiving Emails but Unable to Send Messages

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Attempting to reply to incoming messages or send new emails to contacts.
Observed behavior: Outgoing messages are not delivered and may remain stuck in the Outbox, despite incoming emails arriving normally.

Before you start

Verify that your device is connected to a stable internet network and ensure that Outlook is not accidentally set to 'Work Offline' mode, as this will pause all outgoing messages.

Solution 1Recommended

Check Mailbox Storage and Clear the Outbox

A full mailbox quota or corrupted messages stuck in the Outbox will prevent Outlook from processing new outgoing emails.

If your email account has reached its storage limit, the server will block you from sending new messages. Additionally, an email with a massive attachment can get stuck in the Outbox, creating a bottleneck that stops all subsequent emails from being sent.

Check mailbox storage

Open Outlook, click on 'File' in the top-left corner, and navigate to 'Info'. Look at the 'Mailbox Settings' section to see how much storage space is available. If the bar is full, delete old emails or empty your 'Deleted Items' folder.

Locate the Outbox folder

Go back to your main Outlook view and select the 'Outbox' folder from the left-hand navigation pane.

Remove stuck messages

Look for any pending emails, particularly those with large attachments. Right-click the stuck message and choose 'Delete', or drag it into your 'Drafts' folder to clear the queue.

Check Mailbox Storage and Clear the Outbox

Tip: If you cannot delete a stuck message because Outlook says it is already transmitting, set Outlook to 'Work Offline' from the Send/Receive tab, restart the app, and try deleting it again.

Solution 2

Run the Microsoft Guided Support Tool

Use Microsoft's official diagnostic tool to automatically detect and repair underlying account and email sending issues.

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Frequently Asked Questions

Why are my outgoing emails staying in the Outlook Outbox?

Emails often stay in the Outbox if they contain attachments that exceed your email provider's size limits, if your mailbox has reached its storage capacity, or if there is an authentication error with your Outgoing (SMTP) mail server.

How do I check my Outgoing (SMTP) server settings in Outlook?

Go to File > Account Settings > Account Settings. Select your email account from the list and click 'Change' (or 'Repair'). Verify that your Outgoing mail server (SMTP) address and port numbers match the specifications provided by your email service provider.

Can working offline prevent emails from being sent?

Yes. If the 'Work Offline' feature is activated, Outlook disconnects from the server and cannot send new messages, though you might still see previously downloaded emails. Navigate to the Send/Receive tab and click 'Work Offline' to toggle it off and reconnect.

Does my antivirus software block Outlook from sending emails?

Sometimes overactive antivirus or firewall software can block the specific ports Outlook uses to send emails (like port 25, 465, or 587). You can temporarily disable the email scanning feature in your antivirus settings to see if that resolves the outgoing message block.

Outlook & Email Problems