Information is blocked from going outside the organization when data is not supposed to leave the tenant boundary for compliance purposes (for example, in U.S. Government organizations: Microsoft 365 GCC, GCC High, and DoD). Reporting a message or file to Microsoft from one of these organizations will have the following message in the result details: Further investigation needed. Your tenant does not allow data to leave the environment, so we could not find anything with an initial scan. You'll need to contact Microsoft support to have this item reviewed.
seemingly contradictory:
You'll need to contact Microsoft support to have this item reviewed. But they already tried to report it to Microsoft and it was blocked? What form of contacting Microsoft support is expected to be used and how is it better? Won't any form of "having this item reviewed" cause it to leave the boundary and go outside the organization?