Can't send emails on behalf of someone else in Outlook
Send On Behalf requires a different permission than just reading someone's mailbox. You need your admin to give you Send On Behalf permission in their Microsoft 365 admin center. It's not something you can set up yourself in Outlook.
When you have permission to read someone else's mailbox, it doesn't automatically give you permission to send as them. Send On Behalf is a separate permission that needs to be granted by your admin or the mailbox owner. Once it's set up, you'll be able to compose emails from their mailbox and the recipients will see it came from them, not from you.
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Skip — I just want a technicianCommon mistakes to avoid
- Asking for Read access when you actually need Full Access. Let your admin know you need to send as them, not just read
- Not restarting Outlook after the admin grants permission. New permissions don't show up until you close and reopen the app
- Trying to set this up yourself in Outlook when it actually needs to be done in the Microsoft 365 admin center
Signs you need professional help
- If your admin has set up Send On Behalf but it's still not working, or if you get an error message, give us a call and we'll check the permissions in the admin center.
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