That may be an issue with the stylus, depending on how it works. For some styluses (stylicies?), they essentially are treated as a finger (think Nintendo DS stylus), but for others, they have electronic guts and stuff (Apple Pencil, etc).
If the stylus is one of the "dumb" ones, then I have no clue what could be going on, but if it's a "smart" stylus, then the issue is likely a hardware one, specifically with either the stylus itself, or whatever component within the Chromebook that the stylus communicates with.
If you're willing to give a bit more information (when did the issue start, have you recently had repairs done for your device, etc.), then it will be much easier for us to help you.
Oh, and also, if the stylus is a "smart" one, is it charged? Have you tried replacing the battery (if that's possible, I know Microsoft Surface styluses use AAAA batteries you can just swap)?