Google Assistant not working on LS-5017 Gold (Water 11)

Hi Guys, I have a LYF LS-5017 Gold and I tried Google Assistant for first time, it was good but if I try to speak "Ok Google" command, my phone doesn't respond to it and only does when I press Mic on search bar. When I uninstall updates and reinstall it, it works like normal but I can't get option to activate it from "any screen" except Google App and Launcher.

Is there any was around I can get Google Assistant to work or atleast "Ok Google" command from Any screen.

BTW I also have a Moto G Turbo and it works on it but not on mine, I want to activate it on mine as Moto G Turbo is of my Mom.

Please help

Regards,
Dc