The ShareGate migration tool does not currently support multiple Active Directory (AD) domains for file shares.
Details
Microsoft AD allows you to store your network information such as names, passwords, and user accounts. The AD Domain Service makes this stored data available to network users and its administrators. A multi-domain environment allows you to set boundaries between networks and give authorized users access to relevant information.
For more information, see Active Directory Domain Services overview.
Impact
If you have a complex Microsoft environment with multiple domains, the app will not locate user permissions across your different domains.
For example, if you use your computer to access Domain A when performing an Import from file share, but a document on the file share contains user permissions for a user in Domain B, the permissions will not be located.
For more information, see What is an Orphaned User?