@thknker
You could have a look at the last few posts on this thread below to check the size of your hosts file to help to confirm it is set up okay.
https://forums.ubports.com/topic/7377/why-uadblock-currently-no-longer-works/22
I think you should be able to see the hosts file from 'file explorer' in /mydevice/etc/, it should be a few MB in size.