How to re-migrate users after the SMTP DNS domain has been moved to the target (4343974)

In some migration scenarios it may be necessary to migrate users after their SMTP/DNS/UPN domain name has been moved from the source to the target Office 365 tenant.

Some accounts receive the following error: "Invalid domain name in the request url"

Once the domain has been removed from the source Microsoft 365 environment, then the source user's email address and UPN will likely change to user@sourcetenant.onmicrosoft.com. Additionally, if the DNS domain is being moved from the target, then it is likely that the target user's email address and UPN have been updated from user@targettenant.onmicrosoft.com to user@domain.com. On Demand Migration (ODM) will need to be made aware of these changes prior to performing additional migrations after a domain move.
 

NOTE: If the the UPN of the source admin account that was used to "Grant Consent" to ODM changes, then you will likely need to regrant consent after the change. We would suggest not making any changes to the target account used to grant consent to ODM.
 

NOTE: Before moving the DNS domain from the source Office 365 tenant to the target Microsoft 365 tenant, ensure that you have another way to login to the ODM Portal if you are logging in using an account that exists in the source Microsoft 365 tenant. This KB article, How to use Access Control to add Users and set their Roles within ODM, explains how to add additional admin users to your ODM organization.
 

Here are the steps:

1.) Remove the DNS domain from the source Microsoft 365 tenant

2.) Add and verify the DNS domain to the target Microsoft 365 tenant

3.) Change Addresses in the target Microsoft 365 tenant to update the user's UPN and primary SMTP address to the newly moved domain, as necessary

4.) In the ODM Portal, navigate to the Accounts tab.

5.) On the Accounts tab, select all accounts that you need to re-migrate | Discovery | Refresh Selected Accounts:
 

6.) After running the map from file or Refresh Selected Accounts task, go to the Tasks tab, single-click on the task and verify there are no errors or warnings in the right-hand details pane.

The steps above should allow for a successful migration of Mail, OneDrive, SharePoint and Teams data.