Remove proxy addresses?

New Contributor

O365 - we were previously on AD Sync, but have now disconnect that a few months back and are full cloud now.

In the past, I removed a leaver (A), and put their email addresses as aliases to an existing member of staff (B) so that they could receive the leavers emails.

Now that leaver (A) is returning.

From the admin console, I have removed the alias emails from the current staff member (B), and waited 24 hours too, but when I try to add the leaver (A) in again, it tells me that their email address in use by B.




The addresses aren't shown in the admin console, and in powershelgl if I look at the A user's mailbox details the aliases aren't there, but if I  use the msoluser check in powershell, A still has proxyaddresses listed for the B user.

I can't work out how to get rid of them, and also don't know why when I removed them from the admin console, the details are still appearing in certain areas.

Any ideas?

5 Replies

Hi Neil,


For that issue, please open a support ticket on Office 365 Portal, something is happening and it's not normal. You have done the correct procedure.

There might be a delay between ExO and AzureAD. Have you tried validating removal of that proxy address at a later time?

Once it's removed from "email addresses" in the portal, its not shown against the mailbox user in powershelgl, but is shown against the corresponding msoluser.  And there doesn't seem to be a command to edit that field.

Speaking to MS Support yesterday, we worked out that if we add the new user with a different address, the system allowed us to add the correct address after the mail account had been created and it all works.

The proxy address is still listed against the proper, and the old user, but mail is only delivered to the correct "emailaddress".

Gut feeling is that some info that was used in the old DirSync days is still showing in the system, and under certain circumstances is used for verification, but isn't actually used in day to day operations.


I'm sorted now, and if I get further ADSync related issues I'll push it further with MS.



@Neil Potter

Out of curiosity, why did you choose to implement the old address as an alias?

IMHO, for various reasons, the most natural (and the most usual, too) choice would have been to use a shared mailbox...


Hi Neil,


Thanks for the update, and yes it seams something from old sync. It make sense now.


Please update this thread if you have more information.