FedRAMP is a certification program that allows federal agencies to use cloud providers for increasingly secure/sensitive government or government-adjacent data.
FedRAMP defines three categories regarding levels of security, Low, Moderate, and High.
The higher the security level the more restrictions are in place.
Box is currently certified as FedRAMP Moderate.
In order to be FedRAMP compliant, your administrator must setup Box in very a very specific way. It is possible that the administrator has further restricted access to Box functionalities.
Consult with your administrator to identify security restrictions in place that might affect the usage of the API.
For FedRAMP compliance, you may use the below URLs for API entry points.