Php extensions

Hi there, I need your Help, please!

I am Using Virtualmin LEMP on ubuntu, I have installed Wordpress along with W3 total cache plugin,

Plugin W3totalcache is recommending to install and enable some Php extensions such as {Redis extension: Not installed HTML Tidy extension: Not installed }

Then I had installed these extensions, using regular commands i.e sudo apt-get install php-tidy etc.

Extensions are installed , but they are not getting recognised by Wordpress and W3totalcache. Any suggestions, what am I doing wrong? How can I enable these Php extensions so they get recognised by WordPress?