For the first connection only, a global administrator needs to consent ShareGate on your tenant. This consent gives ShareGate authorization to access the resources needed to crawl your environment and the permissions needed to use ShareGate Management.
Note: For the consent to take effect, the tenant requires an active SharePoint Online license.
Why is consent needed?
ShareGate is a multi-tenant application registered in the ShareGate Azure Active Directory as an Active Directory Application. ShareGate uses resources from Azure, Microsoft Graph, and SharePoint Online APIs to perform certain actions. Some of the permissions required are delegated permissions, which is why a global admin must consent on behalf of all users in your tenant.
For more information on permissions, see Which permissions does ShareGate need?
Who can access ShareGate Management?
Once a global administrator has consented ShareGate, any global admin, SharePoint admin, or groups admin can log in to ShareGate Management with their Microsoft 365 account.
For more information, see How can I manage access to ShareGate?