I'm doing a Office 365 Cutover migration and get a error for 1 user. Office 365 was setup with the default user named firstname.lastname@example.org. But the mailbox that I want to migrate from the existing exchange server had also the name email@example.com. So I get the error: ProvisioningFailedException: The name "admin" is already being used. Please try another name.
I have tried to change the username in Office 365 for this default account that already exists but that didn't work. And when I delete this account then the migration is not working anymore and get the message "failed" for all mailboxes. It look likes that Office365 is using the default account or something for the cutover migration.
So is there a workaround that I can use so that I can migrate the firstname.lastname@example.org account?