Migration Failed: ProvisioningFailedException: The proxy address is already being used by the proxy addresses or LegacyExchangeDN.

Question

I am attempting a cutover migration from Exchange 2010 to Office 365 / Hosted Exchange. Most of the mailboxes migrated successfully but my own mailbox has failed. It consistently fails with this warning:

Error: ProvisioningFailedException: The proxy address "SMTP:*** Email address is removed for privacy ***" is already being used by the proxy addresses or LegacyExchangeDN. Please choose another proxy address.

Note: I have replaced the actual email address with *** Email address is removed for privacy *** and will try to use that consistently throughout.

Research on this error shows that the email address is in use in Hosted Exchange and that I should identify the mailbox with the SMTP address and correct it. It should be noted that when I created the first manual account under our domain I used that same email address (since it is my email address and there was no warning that I should create a fake / new email). I have since changed the email address of that user to be *** Email address is removed for privacy *** (added "office" at the end of it) to avoid potential conflicts. This did not help.

My research shows that I should be able to identify the mailbox or distribution group using the email address with the following powershell command:

Get-Recipient * | Where {$_.EmailAddresses -match "*** Email address is removed for privacy ***"} | ft Name, RecipientType, EmailAddresses

Note: I first tried to use Get-Recipient, which works with my on-premises Exchange 2010 but it fails in Office 365. I found a workaround, which is to use Get-Recipient * instead.

Running this returns no result, but I can confirm it is formatted correctly by running it against other valid email addresses known to exist in Hosted Exchange.

When I run the same command in my on-premises Exchange I find only one result - the account that will not import.

I then tried getting the full list of all email addresses associated with the account, in case the error incorrectly reported the primary SMTP address instead of the conflicting one. I used the following command to do so in on-premises Exchange:

get-recipient | Where {$_.EmailAddresses -match "*** Email address is removed for privacy ***"} | select -expandProperty EmailAddresses

I then ran get-recipient against every listed email address, including the weird ones like MS:, X400:, and CCMAIL:. In no case did I find more than one recipient listed in our on-premises Exchange.

I read in a post on the error that the issue could be a distribution group, so I got a list of all email addresses for all distribution groups and compared them to the email addresses in the account and there was no match. I got the email address list using:

get-distributiongroup | select name, emailaddresses | Export-Csv C:\distributiongroups_hosted.txt

My final step was to run the get-recipient * commands on the Office 365 hosted exchange server, to see if any of my 25 email addresses was somehow listed with another account. Despite being incredibly slow to run, it completed successfully and no email address in my account is listed with any recipient using the get-recipient * command.

Answer 1

Hi BenGraham6018,

We can use Azure PowerShell to check if there is any user with *** Email address is removed for privacy ***. 

1.  Connect to Azure AD

msdn.microsoft.com/.../jj151815.aspx  

2.  Please run Get-MsolUser -UserPrincipalName *** Email address is removed for privacy *** to check if the impacted user exists.
3.  If the user exists, please perform the following cmdlets to hard delete the user.

1). Remove-MsolUser -UserPrincipalName *** Email address is removed for privacy ***

2). Remove-MsolUser -UserPrincipalName *** Email address is removed for privacy *** -RemoveFromRecyclebin

After you have done the steps above, please create a new cutover migration to see if the issue persists. 

Regards,

Johnny Zhang

Answer 2

I found the two accounts - they were set up when we were investigating Power BI. Somehow it created Active Directory users with our UPNs months before we created the Office 365 account and registered our domain. Deleting the active directory users fixed the problem.

Answer 3

I have previously stopped and deleted the migration when I first encountered this problem.

You say "Make sure there is no related UPN (*** Email address is removed for privacy ***).  How do I do that?  You reference "remove-msoluser" but there is no corresponding "get-msoluser" that I can find.

Answer 4

Hi BenGraham6018,

If you run Get-Recipient cmdlet using Exchange Online PowerShell, and no result can be returned, it shows there is no related email address in cloud. Given the situation, to exclude the temporarily issue, please stop the cutover batch and delete it. Please also make sure there is no related UPN(*** Email address is removed for privacy ***) in cloud(If you have one, you need to hard delete the UPN via Remove-MsolUser -UserPrincipalName *** Email address is removed for privacy *** -RemoveFromRecyclebin). Then re-create a new cutover migration batch and run it. 

If the issue persists, please help perform the following cmdlets in private message that I have sent to you for further checking.

Get-mailbox *** Email address is removed for privacy *** |fl via local EMS

Get-MigrationUserStatistics -Identity *** Email address is removed for privacy *** -IncludeReport | FL via Exchange Online PowerShell

Please click on the link below to access to your Private Message.

">community.office365.com/.../conversations 

Regards,

Johnny Zhang