My Note 3 S Pen doesn't work at all, any advice?

[AC Question]

Note 3 S Pen Doesn't Work at All

I can't use my s pen, like there's something wrong but idk where is it. I've bought the new one(the s pen) but it still not working at all. But when i use it on another phone (galaxy note 1) it was working. It's start to not working at all after i upgraded my phone to lollipop. Any advice? I need to use the pen for my task. Thanks.