[Docker] docker build RUN apk update Error

Step 3/7 : RUN apk update

 ---> Running in 2fdba320b542

fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz

fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz

ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.9/main: temporary error (try again later)

WARNING: Ignoring APKINDEX.b89edf6e.tar.gz: No such file or directory

ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.9/community: temporary error (try again later)

WARNING: Ignoring APKINDEX.737f7e01.tar.gz: No such file or directory

$ docker build --tag shlee/springboot-cicd:latest --no-cache --network=host .

 --> Add "--network=host" ..