Outlook 365 - sending on behalf of another email address

Posted on 2013-12-11
Last Modified: 2013-12-29
We have a user who has a full email account and supports Joe Smith.
Joe Smith has 2 emails. and is setup as an alias and is set to forward to  Those emails come in and Bob forwards those to Joe when he needs to see them.  

If Bob wants to reply to or send from (on Joe's behalf), Bob tries to send and gets a pop-up that says he does not have permissions to send on behalf of even though the permission has been granted.  

We double checked the permission and it was granted, we unchecked it and put it back on and it still does not work.

Anyone have any idea why we would have this problem?

Many thanks for any help you can give!!!
Question by:janmishkin
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LVL 13

Expert Comment

by:Ugo Mena
ID: 39712312
It is possible, but the correct method for doing this is to create a distribution group within Exchange and then (using powershell) to assign "Send-As" permissions to that distribution group.

Users will then be able to receive and send mail, appearing as "From" that email address (rather than their default primary SMTP).

MS Outlook Help Article:
Give Users Send As Permission:

Author Comment

ID: 39712354
Bob still needs to be able to send out email from himself; wouldn't this scenario prevent that?
LVL 13

Expert Comment

by:Ugo Mena
ID: 39712425
Sorry. On second thought, it is not possible to send messages from an email alias for any user. While the PowerShell command to set the Send As permission could run successfully, after the email is sent out, the From field would still be the primary address instead of the alias.

It is true that you could set an proxy email address as alias in Office 365 and the user could receive emails from both his email address and the alias. However, it would not be possible to send messages from the proxy email address.

Here is the description from the Proxy Addresses article:

"When you add proxy addresses to a user's account, you are simply adding SMTP addresses to the existing mailbox. The proxy addresses you create are all associated with the primary e-mail address and any e-mail sent to the proxy addresses goes to the mailbox for the primary address. "
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Accepted Solution

janmishkin earned 0 total points
ID: 39712647
Our programmer just looked at the issue; he opened up the portal at as the administrator and clicked on's email.  He then went to the "mail flow" area and added to the "on behalf of" table.  

To me this is completely backwards, it should be just the opposite and our other users have it set up just the opposite way around BUT it is now working.  This is totally illogical.

The only issue on this is that it does not say "on behalf of 'Joe's Office' " which is is how all the others and set up but since the username is "Joe's Office" it is pretty obvious that Joe may not be sending this out.

Author Comment

ID: 39712652
Unless anyone can explain why this is working this way, I guess this should be closed.  Thanks for all thoughts.
LVL 13

Expert Comment

by:Ugo Mena
ID: 39712705
Strange. I just logged into our Office 365 admin portal and do not see those settings in Mail Flow.

However I do see the Send As, Send On Behalf Of and Full Access settings within each users Mailbox Delegation tab. See attached.

Author Comment

ID: 39712735
You are correct, my mistake.  We bounced around so many screens in the last hour that I'm a bit dizzy from the ride.  Thanks for the clarification.
LVL 13

Expert Comment

by:Ugo Mena
ID: 39712754
right on. An ditto on being dizzy... I just checked the date on the link i attached: Topic Last Modified: 2011-03-19 Uhhggg! Sorry! Even though it says it Applies to: Office 365 for professionals and small businesses, Office 365 for enterprises, Live@edu That was for when Office 365 was called BPOS and was not fully on Windows Azure Platform.
Glad you got it to work.

Author Closing Comment

ID: 39744513
The solution is good because it works; but it is illogical because of the application.

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