"Microsoft GCC High Government-Specific Cloud Security" is a specialized cloud offering from Microsoft designed to meet the stringent regulatory requirements of U.S. government agencies, contractors, and other organizations handling sensitive information. This cloud environment is tailored specifically for the U.S. Department of Defense (DoD), federal agencies, and entities adhering to high-level compliance standards.
You can tell if a company is using GCC High by using this URL and substituting the company's Domain Name:
https://login.microsoftonline.com/<domain name here>/.well-known/openid-configuration
You will see an output like the following:
Look for the following in the code: "microsoftazure.us" or "usgovcloudapi.net" or "USGov"
If you have a tenant in Azure Public in North America, the "tenant_region_scope" attribute’s value will be "NA"
OneDrive sharing between a Microsoft GCC High Security account and a commercial cloud account is not supported without special configuration that CG does not want to get into with GCC clients.
Workaround: a group "Owner" can right-click a folder or file within SharePoint Documents folder and share with the GCC High Security end user.
Reference Ticket: https://helpdesk.connorgp.com/a/tickets/71980