Tenant to tenant migration error

Hi Ben_H3,

you are encountering a "CommunicationErrorTransientException" with the error message "The call to 'https://mw4pr07mb8700.namprd07.prod.outlook.com:64350/mrs/Microsoft.Exchange.MailboxReplicationServi...' failed."

That could be the issue with Admin consent to the application in the source tenant.

Make sure you used correct tenant domain in the consent URL.
Also, make sure your OAuth Application ID is associated to the Migration Endpoint.

Cross-tenant mailbox migration - Microsoft 365 Enterprise | Microsoft Learn

Please click Mark as Best Response & Like if my post helped you to solve your issue. This will help others to find the correct solution easily. It also closes the item. If the post was useful in other ways, please consider giving it Like.

Kindest regards

Leon Pavesic