Encountering a duplicated proxy address error on the step "Add email address to target" of a mailbox cutover
Error message from cutover log file
Write: Set-Mailbox: Error setting properties.
System.Exception: Error executing PowerShell script.
Set-MailBox -Identity "<VALUE>" -DisplayName "<VALUE>" -EmailAddresses "X500:/o=ExchangeLabs/ou=Exchange Administrative Group (<VALUE>)/cn=Recipients/cn=<VALUE>, SMTP:LDF_<VALUE>, x500:/o=ExchangeLabs/ou=Exchange Administrative Group (<VALUE>)/cn=Recipients/cn=<VALUE>" -HiddenFromAddressListsEnabled:$False -Name "<VALUE>" -Confirm:$False
The proxy address "x500:/o=ExchangeLabs/ou=Exchange Administrative Group (<VALUE>)/cn=Recipients/cn=<VALUE>" is already being used by the proxy addresses or LegacyExchangeDN of "<VALUE>". Please choose another proxy address.
NotSpecified: (<VALUE>:ADObjectId) [Set-Mailbox], ProxyAddressExistsException
at CDS.AzureLibrary.AzureAD.CheckErrors(PowerShellWrapper psw, String[] ignoreErrors)
at CDS.AzureLibrary.AzureAD.SetMailbox(PowerShellWrapper psw, BTObject btUser, BTObject btExisting, HashSet`1 alreadySet)
Remove the target contact object
Run the cutover step again.
If there's no target contact, we recommend running the cutover again, Re-running the cutover for the final step of task 4 in the domain cutover should resolve the errors about duplicated proxy addresses.
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