If you are having issues with your Xencelabs Pen Tablet in Clip Studio Paint, the instructions below will walk you through removing the user preferences in Clip Studio Paint. This might be what is causing your issue. Once you have removed the preferences, please test your Pen Tablet.
Note: This will reset all of your CSP Tool Settings that you have made.
1. Close Clip Studio Paint.
2. Start Clip Studio and then click on [PAINT] in the upper left corner while pressing Shift.
Note: Hold down the [Shift] key until the [Reset to original defaults] dialog box appears.
3. Check the items to be reset in the [Initial boot] dialog box and then click [OK].
Here we have checked Tool.
4. Clicking [OK] on the confirmation dialog box will reset the checked item(s).
Please test the Pen, both the nib and the eraser side.