Help for the migration configuration

Question

Hello

Please i need your help on this issue.

I need help with the migration configuration from Google?

I've tried to follow the official guide but I've some issue while creating the contacts, on the prerequisites: https://learn.microsoft.com/en-us/microsoft-365/admin/moveto-microsoft-365/migrate-email?view=o365-worldwide

The issue is when I create the new email user contact(as in the screen). The User ID is the account I want to migrate that exists as mailbox.

The error is: Mail user creation failed!

The proxy address "SMTP:andrea.xxxx@digxxxx.com" is already being used by the proxy addresses or LegacyExchangeDN. Please choose another proxy address.

Answer 1

Hello, @IniobongNkanga-8038,

Welcome to the Microsoft Q&A platform!

According to the error you have shown, the proxy addresses you're trying to use is already in use in your existing environment, which is causing the conflict. This issue generally occurs when the email address you're trying to assign to the new mail user is already associated with an existing user or contact in Exchange.

Here are a few steps you can take to resolve this:

1. Check for Existing Objects: Use the Exchange admin center (EAC) or Exchange Management Shell (PowerShell) to search for any existing mail users, mail contacts, or mailboxes that might already be using that address.
2. Remove or Update Conflicting Addresses: If you find that the email address is already in use, you can either remove it from the existing object or update the existing object to use a different email address.
3. Use a Different Proxy Address: If the email address is not in use, try using a different proxy address temporarily to create the mail user. Once the user is created, you can update the proxy address to the desired one.
4. Confirm Proxy Address Assignment: Ensure that when you're creating the new mail user, you are not accidentally reassigning an address that is already in the system.
5. Check LegacyExchangeDN: The conflict sometimes can be due to a LegacyExchangeDN value. You might need to update or remove conflicting LegacyExchangeDN entries if they exist.

Get-MailUser -Identity "ExistingUser" | Format-List LegacyExchangeDN

If the issue persists, you can use PowerShell to create the mail user and specify the proxy addresses. This can sometimes bypass issues encountered in the GUI. Here's an example of how you can use PowerShell to create a mail user:

New-MailUser -Name "Andrea" -ExternalEmailAddress "andrea.xxxx@digxxxx.com" -UserPrincipalName "andrea.xxxx@yourdomain.com" -Password (ConvertTo-SecureString -String "YourPassword" -AsPlainText -Force)

Moreover, troubleshoot an email migration is offered for your reference: Troubleshoot an email migration - Google Workspace Admin Help.

(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

Should you need more help on this, you can feel free to post back. 

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Thank you for your support and understanding.

Best Wishes,

Alex Zhang