Recently, after unlocking my phone screen (Samsung J7 Pro - J730, stock ROM, Android 7 Nougat), I usually receive a toast notification saying: "Failed to init Google DNS, switch to host IP method". I can guess that the toast is made after a network change (from WiFi to 3G and vice versa) because that's how it usually happens, like when I go home and the phone catches the WiFi signal. Maybe the "Google DNS" refers to the 184.108.40.206 public DNS server owned by Google.
Problem is: (1) I don't modify the network configuration at all. My IP is set to DHCP, not static and not manually configurated. And (2) it even happens on 3G network, which I cannot configure the DNS in anyway.
I have looked for the toast message everywhere and I could not find any reference at all.
My questions are:
What is the source of this toast? Have any of you encountered this as well?
Is this a security concern (location tracking, hacking attempts, surveillance, etc.)? Should I be worried about this at all?