Something is blocking ads and I don't know what it is
Somebody gone borked up their hosts file

Luckily, it's an easy fix. Your going to need root, and a root file manager (Like ES file explorer)

In your file explorer, go to /system/etc, and look for a file called 'hosts'. Open it, and remove EVERYTHING except the top line to disable the AD blocking. If you want to, of course

But why?

AdAway and similar apps use root auth to write to the hosts file the locations of ads. This then blocks them due to what said file does (it's a blacklist, essentially)