Fetch APKINDEX hangs

Docker Desktop for Windows
1

fetch APKINDEX hangs

Step 4/16 : RUN apk update && apk upgrade       && apk add --no-cache --update  ca-certificates         bash    wget    curl    tree    libxml2-utils   putty   git     && rm -rf /var/lib/apt/lists/*     && rm -rf /var/cache/apk/*
 ---> Running in 5f3257b0b676
fetch http://dl-cdn.alpinelinux.org/alpine/v3.5/main/x86_64/APKINDEX.tar.gz

exec’d in to nslookup but got can't resolve '(null)'

docker exec -it 5f3257b0b676 bash
bash-4.3# nslookup dl-cdn.alpinelinux.org
nslookup: can't resolve '(null)': Name does not resolve

Name:      dl-cdn.alpinelinux.org
Address 1: 151.101.48.249

My daemon config contains the correct DNS servers
"%programdata%\docker\config\daemon.json"

{
    "debug": true,
    "disable-legacy-registry": false,
    "dns": ["135.70.10.20", "135.70.10.30"],
    "tlsverify": false
}

I’m on
Windows 10 Version 1607 and running using Command Prompt
Docker for Windows version 17.06.0-ce, build 02c1d87