In Microsoft Dynamics 365 Customer Engagement/ Sales, is it possible that I can disable/ block the global discovery service from returning information about any of the environments in my organization?
For some internal security reason, I want to disable the global discovery from listing our internal Dynamics 365 environments.
No, you cannot turn off Global discovery. It is however, only accessible via User Auth and results are filtered by that user. The calling user must have an account in an environment for that environment to be shown.
As Filburt comments, you can restrict environments that are shown to users by using security groups associated with the environments to limit access.
See: https://learn.microsoft.com/en-us/power-platform/admin/control-user-access#associate-a-security-group-with-a-dataverse-environment