WHERE your case fans are plugged in is important. Your post calling them "just normal fans" makes me suspect you have plugged them into mobo fan headers. Is that right?
As I recall, the NZXT CAM software utilituy normally is used with their "Smart Device" item often included with their cases. It is a fan hub that gets its control signals from CAM via a cable connecting it to a mobo USB2 header. So for CAM to control your fans, you need the Smart Device, and it needs connections to a SATA power output from the PSU and to the USB2 header, and the fans have to be plugged into that Smart Device. If you have your fans connected to mobo headers, then it is the MOBO itself that controls and monitors them, and the CAM utility does not have...