Office 365 – Send As Alias – Outlook 16.44 for Mac

Office 365 – Send As Alias – Outlook 16.44 for Mac

  • Posted by DIY Chris
  • On January 5, 2021
  • 365, alias, exchange, exchange alias, exchange send as, exchange send as alias, office, office 365, office 365 alias, send as, send as alias

So I recently had the idea that I could use Office 365 for all of my domains for e-mail hosting and only pay for a single user license subscription by adding all of the domains and then creating aliases under the single user mailbox for the additional domains. However, I hit a road block and that is while it works perfectly well for receiving messages to those aliases (you can even create mail rules to filter these out to specific folders to keep things organized) – I was unable to send e-mails from these aliases. I started doing some research online and found a few solutions but they all seemed cumbersome to setup as well as maintain. So I found a solution that partially worked and perfected it.

What follows is a step by step guide for getting this to work. All you need is a basic subscription to Office 365 for Business, which is $5 / month / user of which we will only need 1 unless of course you have more than one physical person that you need an e-mail for. In my case I have multiple domains that I need to have contact e-mail addresses for.

This guide assumes that you’ve already subscribed to Office 365 for Business and have at least 1 user account created with an active license. This guide further assumes that you’ve already added the domains that you want to create aliases for to Office 365.

Note: This works both for aliases on the same domain and any other domain that you add to Office 365

Another Note: Some steps in this guide may not be required. I had to do some additional things to make this work on the latest Outlook 16.44 for Mac

STEP 1 – Create a Group:

  1. Log into the Office 365 portal
  2. Go to the Exchange Admin Center
  3. Under Recipients go to Groups
  4. Next to New Microsoft 365 group click on the drop down
  5. Select Distribution List (Read below Why do I need to choose Distribution List)
  6. Name it whatever you want
  7. The Alias will be the name before the @ in the e-mail address so if you’re making then the Alias will be info
  8. The Email address field should be auto populated with the Alias
  9. After the @ in the e-mail address is a drop down, choose the domain that you want to create the e-mail address for
  10. Scroll down to Members and then add the mailbox that you want this e-mail address associated with
  11. For security you should change Open to Closed in Choose whether owner approval is required to join the group
  12. Click Save, Click Ok

Congratulations, you created a mail enabled distribution group but we are not done just yet. We need to change a few settings.


STEP 2 – Modify the Group:

  1. Double Click on the group you just created in Exchange Admin Center
  2. From the options in the left, click on Group Delegation
  3. For Send As and Send On Behalf, add the mailbox that you want this group associated with (Read below why do I need to add a mailbox to Send As and / or Send On Behalf)
  4. From the options in the left, click on Delivery Management
  5. Select the Senders inside and outside of my organization radio button
  6. Click Save
  7. Click OK

Congratulations on completing the second step. Let’s finish up in Exchange Admin Center by doing just one more thing. We need to convert the Distribution List to an Office 365 Group.


STEP 3 – Convert the Group:

  1. Refresh the Page
  2. Under Recipients go to Groups
  3. Click on the “Upgrade Distribution Lists” button with the red New banner below it, its right next to the dropdown which is next to the New Microsoft 365 group button.
  4. A dialog opens showing you groups that are available for upgrade.
  5. Check the box next to the group you just created
  6. Click Start Upgrade
  7. A dialog window opens stating that the Upgrade is in progress
  8. Click Ok
  9. Close the dialog
  10. Refresh the page
  11. Under Recipients go to Groups
  12. Find the group you created and verify that the group type is Microsoft 365

Perfect, you should now have a Microsoft 365 group with the e-mail address (alias) that you wanted to add to your licensed account. To send messages from this e-mail address we just need to do one more thing and that is to configure the client. Note: You don’t have to do this if you’re using the web version of Outlook, this only has to be done if you are using the desktop app!

STEP 4 – Configure the Outlook Client:

  1. If you are using Outlook in the “New Outlook” mode you’ll have to turn that off because this functionality doesn’t work with the “New Outlook”
  2. Click on Outlook -> Preferences
  3. Click on Accounts
  4. Unless you’ve already added your 1 licensed account, you’ll need to click on the + at the bottom and click on New Account.
    1. Put in your e-mail and click continue
    2. Finish the rest of the setup instructions
  5. Back in accounts, click on the account you just created
  6. Click on Advanced
  7. Click on Delegates
  8. At the bottom “Open these additional mailboxes” click the + button
  9. Type the e-mail address of the group you created
  10. Click Add
  11. Click OK
  12. Close the Accounts Dialog

You should now see an additional mailbox on the left side along with all of your other accounts. You’ll see that the mailbox has its own set of folders (Inbox, Drafts, Sent, etc..)

Now when you go to send a new message, you can select that e-mail address in the From drop down.


Why do I need to choose Distribution List?

Because if you want to create a group for a different domain that is not the same as that of the primary account, then choosing Microsoft 365 group does not work because it doesn’t allow you to create a group for other domains.


Why Do I need to Add a Mailbox to Send As and / or Send On Behalf?

In order to be functional the group requires the mailbox who will utilize this e-mail to have the permission to send e-mails from that group.


Why Do I need to convert to a Microsoft 365 group?

The group won’t show up in the Outlook client as a mailbox unless the group is a Microsoft 365 group. Also sending as from the Outlook client doesn’t work unless the group is a Microsoft 365 group. However, you can send from groups that are not Microsoft 365 groups from the Outlook web client which is weird but it does work.


Note: At the time that I wrote this article I was rightfully confused and was wrong that you couldn’t create a Microsoft 365 group for a different domain other than the primary while in the Exchange Admin Center. However, if you are trying to create a Microsoft 365 group from the Office 365 Admin, the limitation exists there so I initially didn’t even think to check if that was a thing in EAC.

Either way. I hope this helped someone out and I hope that Microsoft fixes the bug in Outlook that doesn’t give you the Advanced button in Accounts to allow you to add delegated mailboxes in the “New Outlook” because I much prefer the newer interface but how does the saying go? Function over form?


Hi, I would like to get few items from you. Can you contact me via email?
Why just not use Shared Mailbox? much simpler. Create shared mailbox with desired email address, add yourself as member. It shows up automatically in Outlook in max 60 minutes.

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