Please follow the below mentioned step in order to resolve the issue:-
>please reset the S pen once and check the issue (Insert the S Pen into the slot>>settings>>S Pen>> open the Air actions>>Tap on top three dots on right corner>>reset S pen).
>If still issue persist, visit the nearby Samsung service center for the physical inspection of the device and S pen.
For address details of Samsung Service centers follow the link mentioned below-
In my case there is problem in phone they change spen from another device and still its not connecting but mine connects to other device that means there is problem in phone and now they are saying that change display and motherboard
