It appears to be Cloudfront blocking by IP address. I don’t know why this happens or how to fix it, but I have the same issue:
$ docker pull alpine:latest
latest: Pulling from library/alpine
ff3a5c916c92: Pulling fs layer
error pulling image configuration: Get https://production.cloudflare.docker.com/registry-v2/docker/registry/v2/blobs/sha256/3f/3fd9065eaf02feaf94d68376da52541925650b81698c53c6824d92ff63f98353/data?verify=1530179808-alwCCgd3HoqN4USNq2%2FXwimOKC4%3D: Forbidden
Works fine on another machine.
Being cynical, maybe they’re blocking IPs to get people to pay for support? 
A workaround is to configure the client to connect via a proxy server:
Of course, if Cloudfront then blocks your proxy server… 