Are you using a Windows Mixed Reality headset? WMR unfortunately blocks the mouse while it is rendering to the headset. You have to press WINDOWS+Y to allow mouse input.
To make matters worse that doesn’t always work while a game is active, you may have to ALT+TAB out of the game, then press WINDOWS+Y and ALT+TAB back into the game.
To avoid this procedure you can cover the headset’s proximity sensor with a piece of tape before using vorpX. Then you only have to press WINDOWS+Y once. Otherwise WMR annoyingly resets this every time you take off the headset.