How to Send Emails from Another Mailbox in Outlook
Sending emails from another mailbox in Outlook allows authorised users to send messages on behalf of a shared mailbox, delegated account, or team inbox without signing in separately. This is useful for support teams, reception staff, managers, and assistants who manage multiple email accounts. This guide explains how to send emails from another mailbox in Outlook and how to troubleshoot common sending issues.
Mailbox Sending Instructions
Method 1: Send an Email from Another Mailbox in Outlook on the Web
Step 1: Sign In
Sign in to Outlook on the web using your Microsoft 365 work or school account.
Step 2: Create a New Email
Click New mail to create a new message.
Step 3: Show the From Field
If the From field is not visible, select Options > Show From.
Step 4: Choose Another Mailbox
Click the From button, then choose Other email address.
Step 5: Enter the Mailbox Address
Enter the shared mailbox or delegated mailbox email address.
Step 6: Complete the Email
Add the recipient, subject, and your message.
Step 7: Send the Email
Click Send.
Method 2: Send an Email from Another Mailbox in Outlook Desktop App (Windows/Mac)
Step 1: Open Outlook
Open the Outlook desktop application.
Step 2: Create a New Email
Click New Email to create a new message.
Step 3: Show the From Field
If the From field is hidden, select Options > From.
Step 4: Select the Mailbox
Click From, then choose Other Email Address or select the shared mailbox from the list.
Step 5: Enter the Address
Enter the mailbox address if required.
Step 6: Complete the Email
Add the recipient, subject, and email content.
Step 7: Send the Email
Click Send.
Method 3: Set a Default From Address (Optional)
Step 1: Open a New Message
Open a new email message in Outlook.
Step 2: Open the From Menu
Click the From dropdown menu.
Step 3: Choose Your Preferred Mailbox
Select the mailbox you use most often.
Step 4: Save Preference
Outlook may remember this selection for future emails depending on your version and settings.
Fix Mailbox Sending Issues
Basic Troubleshooting
- Confirm Permissions
Confirm you have permission to use the mailbox. - Check the From Field
Check that the correct mailbox appears in the From field. - Restart Outlook
Restart Outlook and try again. - Wait for Sync
Wait a few minutes if access was recently granted.
Advanced Troubleshooting
- Check Send Permissions
Verify whether you have Send As or Send on Behalf permissions. - Re-add the Mailbox
Remove and re-add the mailbox from the From address list. - Test Outlook on the Web
Test sending from Outlook on the web to determine if the issue is desktop app related. - Refresh Sign-In
Sign out and sign back into Outlook to refresh permissions. - Review Delegation Settings
Ask your Microsoft 365 administrator to confirm mailbox delegation settings. - Check Cached Profiles
Check whether cached Outlook profiles or old credentials are causing sync issues.
Important Mailbox Sending Notes
- You must be granted access before sending from another mailbox.
- Some organisations allow Send As, while others use Send on Behalf.
- The sender name shown to recipients depends on your permission type.
- Permission changes may take time to sync across devices.
- Always confirm the From address before sending important emails.
- Sent messages may be saved in either the shared mailbox Sent Items folder or your personal Sent Items folder depending on configuration.
Mailbox Sending FAQs
Why can’t I send from another mailbox in Outlook?
You may not have the correct permissions, or Outlook may still be syncing recent access changes.
What is the difference between Send As and Send on Behalf?
Send As shows the mailbox as the sender. Send on Behalf shows that you sent the message for that mailbox.
Why is the From field missing?
The From field may be hidden by default. Enable it from the message options menu.
Can I send from a shared mailbox on mobile devices?
Some mobile Outlook apps support shared mailboxes, but features may vary depending on the device and app version.
Where do sent emails appear?
Sent messages may appear in the shared mailbox Sent Items folder or your own Sent Items, depending on your organisation’s settings.
Mailbox Sending Complete
Sending emails from another mailbox in Outlook is an efficient way to manage shared or delegated communications while staying signed in with your own account. Once permissions are in place, you can select the mailbox in the From field and send messages normally. If you continue to experience issues, please contact Swazzy Support for further assistance.
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