This message usually pops up when trying to load an incompatible XML file, e.g. a file which was created for a different camera. But there's a second possible cause: Some mvBlueCOUGAR-X(D) cameras from before the IMX era start with the DeviceSpecific InterfaceLayout. Make sure your application sets the InterfaceLayout to GeniCam before opening the camera.

Set InterfaceLayout