Office 365 Send As an Alias

If you want to have a single mailbox on Office 365 and be able to send as aliases of that mailbox, you will need to do some work around as it is not really support by Microsoft, see:

1 – Create Distribution List

  1. Create distribution group for the desired email address (ensuring is does not exist as an alias or otherwise in the tenant)
  2. Add desired destination mailbox as a member
  3. Open the Exchange Admin center
  4. Select “recipients” (side navbar) -> Select “groups” (top) -> Select the distribution group you just created, click the pencil icon to edit
  5. Select “group delegation” add your main mailbox user to the ‘Send As’ list
  6. Wait for approx 30 mins for Office 365 to provision the distribution list and update contact lists
  7. Optionally set up message rules in your mailbox to ensure emails to the distribution list email address are put into a specific folder

2 – Send As the distribution list via Outlook (Windows)

  1. In your Outlook client, create a new message
  2. If you cant see the From box, click ‘Options’, Click ‘From’
  3. Click on the now display ‘From’ dropbox and select ‘Other email address’
  4. Click on the ‘From…’ in the popup box
  5. Click on the ‘Offline Global Address List’, select ‘All Distribution Lists’, select your desired From address.

3 – Exchange Online

  1. Create new message
  2. Click the ellipsis to the right of the send button
  3. Right click on the from address, click remove
  4. Start typing the address you want to send from, select it from the drop down autocompleter

5 replies on “Office 365 Send As an Alias”

Method $3 just does not work if you are sending as your non-default SMTP address (alias).

Thanks for this.
Another trick is that I got an error “Object reference not set to an instance of an object” when trying to add a Delegate using the New Exchange Admin Center. I switched to the Classic admin center and it worked fine. Hopefully this is a glitch that MS will fix before stumping anybody else.

Had the same issue as mark-e-mark when trying to add a delegate to a distro list…worked after switching to the classic admin center. As one of my ex-colleagues used to say, “this is a stupid problem to have.”

I’m grateful your little site here came up in a search, as I was scratching my head!

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