If you shoot AF-C focus priority then you have to configure the AE-L/AF-L button to lock focus and press that when you shoot.
If you shoot that way and are using a grip in vertical mode then ask Nikon how to do that (a pet peeve of mine).
If you shoot AF-C release priority or Focus+Release then the shutter should fire regardless of focus.
I suspect you have the camera set to AF_C Focus Priority *AND* the shutter button also activates focus (AF Activation is turned ON). In that case the camera will refocus when you hit the shutter button to fire. But you did not say precisely what is causing you to not have much success