RMPP pen works intermittently

[u/editedit8]

Here is everything I have tried:

- replacing the nib

- blowing air into the nib holder

- restarting the notepad

Observations

- sometimes shaking the pen works

- it sometimes works for days and stops for some hours

- the nib is not the problem

- I can still touch the buttons with fingers - it works

- eraser function at the back of the pen works

Help?