Install Zoom: cannot find package libxcb-xtest0

My OS Linux Mint 18.3, xfce, 64 bit. Have tried e.g. this: Have also tried to install Zoom from application center and also from zoom website. I have also tried the suggested solutions here. Can anybody give me an idea how to solve the problem? And: I am not a professional linux user, almost a newby... Thanks a lot!