How to Send Email from a Shared Mailbox in Power Automate

1. Give the flow's account permission

In the Exchange admin center, open the shared mailbox and grant Send As to the account your flow's Outlook connection uses (ideally a service account). Permission changes can take a while to apply, so test again later if it fails at first.

2. Use the shared mailbox action

Add 'Send an email from a shared mailbox (V2)' from Office 365 Outlook. Enter the shared mailbox address in Original Mailbox Address, then fill in To, Subject and Body as usual.

Alternatively, 'Send an email (V2)' has a From (Send as) field under advanced options that does the same job.

3. Fixing common errors

• 'The specified object was not found in the store': the account doesn't have permission yet, or the mailbox address is misspelled.
• Email sends from the wrong address: you used 'Send an email (V2)' without filling in From (Send as).
• Works for you but not a colleague: each person's connection needs its own Send As permission. A service account avoids this.

Reading the shared inbox too

To start a flow when mail arrives, use the trigger 'When a new email arrives in a shared mailbox (V2)'. The account needs access to the mailbox for this to work.