plugin no have boton SAVE here https://prnt.sc/fk0anhV81Qvm

looks like you have hidden php error there -> debug -> logs -> review.

i does this i ver see in DEB

error here https://prnt.sc/AkY6YcffdGSq

error https://prnt.sc/mIr4Mo5odAYq

i try my site en 2 server company VPS error y HOSTING SHARED error
PLESK and Cpanel error in Theme, PLugin and osclass

Looks like you have something wrong in plugin configuration - decimals.
You can also update in that file this line:
  $decimals = ($custom_decimals <> -1 ? $custom_decimals : osp_param('price_decimals'));

into:
  $decimals = (int)($custom_decimals <> -1 ? $custom_decimals : osp_param('price_decimals'));


i fixed thank