unable to migrate

Hi All,

I am using an Exchange 2016 hybrid environment and facing an issue migrating a user from on-premises to online. I am seeing the error below.

I tried using the Enable-RemoteMailbox syntax from on-premises, but it did not work since the mailbox already exists in the on-premises environment.

Enable-RemoteMailbox -id "user1" -RemoteRoutingAddress "user1@contoso.mail.onmicrosoft.com" -alias user1
This task does not support recipients of this type. The specified recipient User1 is of type UserMailbox. Please make sure that this recipient
matches the required recipient type for this task.

If I delete the mailbox from the on-premises Exchange and execute the Enable-RemoteMailbox command, will it work?

Please note: I do not want the Active Directory account to be deleted, as I cannot recreate the account in AD. In our environment, AD accounts are created by an IAM tool.

Could someone guide me on how to delete the mailbox in on-premises Exchange without deleting the associated AD account or guide me how to troubleshoot migration error.