You are the author of [How To] Install Pi-Hole in Docker: Update - 08/10/18 right?
Care to elaborate
- why do you suggest configuring a DNS server manually (why do you think this is needed at all?)
- why do you suggest using Google's server when it's about using Pi-Hole (do you catch the irony handing out your whole surf history to Google? Some people recommend using Cloudflare's 184.108.40.206 in the meantime but this doesn't improve things a lot)