Same problem here, pretty much. Also using Galaxy S6.
I configure the wifi as instructed, "localhost" & "2020", but almost every time that i leave the wifi signal (or close whichever browser or application i was using), the connection seems to be forgotten and i get connection errors.
So then i reopen the Adblock Plus app, and it gives me the same old message about configuring the connection.
HOWEVER, when I go to manually configure the network proxy settings, they're usually still set to "localhost" & "2020".
So then I re-save them, and sometimes the connection works... for a while.
But other times it doesn't, and i end up needing to reset the network settings to the original NON-PROXY defaults in order to get any connection at all in any browser or app.
Has there been any updates to the replies to the OP's question? Or to any similar questions? I don't see any conclusion in this thread.
I've been leaving Adblock Plus disabled most of the time now, because i can't reconfigure the proxy settings EVERY time I connect to ANYTHING. Even apps like Facebook or the weather app on my phone's home screen don't connect otherwise.