S, D, and C keys not working together

I have a peculiar issue with my input. I’m making a 3D game in which you use WASD to move, and hold the C key to sprint. All of the keys have been assigned buttons in the Input manager, and my code reads from the Horizontal and Vertical axis inputs in order to achieve movement. The weird part is, I can’t sprint by holding C when also holding down S and D (moving backwards and to the right). I can sprint when holding down any other key combination, and just holding down S and D to walk works fine. Any idea what might be causing this?

You can try this, it may be your keyboard.