Sharebar cant be fixed on right in centre

Hi support,

i have set up the sharebar on my website(www.fittestbody.nl)(NOT ON MY HOMEPAGE). It works great, but when i scroll down on all my pages the sharebar doesnt stay at the center of the right side(as you can see on this page; https://www.fittestbody.nl/klantervaringen/).

And on this page(https://www.fittestbody.nl/prijzen/) its not on the right side, but floating in the screen. I think this is due to the fact that i dont have a sidebar on this page, on the other pages i have a sidebar on the left.

Could you please help me, i have tried css already, but i cant find where to place the correct code:(

https://www.ads-software.com/plugins/sharebar/