That is a very important explanation. One nice thing about dnscrypt-proxy2 was in my view, that I don't have to care about DNS servers (which may occassionally be out of service).
Still, I think it is fairly simple and I don't have to care for DNS server credentials. So I selected a couple, checked the log, checked DNS validation, and done.
Good advice, guys @aidanharris and @ninjanoir78.
Cheers
Oscar