Stylus is not working with iPad mini 4

Hello,

I'd recently bought Adonit Pixel for my iPad mini 4. It should be compatible with it, however the pressure sensetivity isn't working well. Also, when i'm drawing sometimes it stopa responding for a moment. I draw in Concepts ( which is compatible with stylus), I turned off multitasking gestures and Idon't use screen protector. Do you have any idea about what should I do to make it work properly (smoothly)?