Swap the keys so you're pressing what you're using for the other combination. Keyboards have a physical hardware limitation on what keys can be pressed at once so that certain combinations don't register. This doesn't mean there's a limit to the number of keys at once, it means specific keys can't be pressed in combation. I can't press Caps Lock, W and G at the same time, but I can press W, D, F, and space at the same time with no issues.