Today, one of my colleagues asked me to try to download a docker image because he encountered a network issue.
Then I tried and found out I had the exact issue as he had.
λ docker pull tiangolo/uwsgi-nginx-flask
Using default tag: latest
Error response from daemon: Get https://registry-1.docker.io/v2/tiangolo/uwsgi-nginx-flask/manifests/latest: received unexpected HTTP status: 503 Service Unavailable
Obviously, this is not a network issue, it's docker's registry issue.
So if you can't wait, you can use a mirror registry to download the docker images you want. Here are two examples.
Docker official china mirror (Fast in China, slow outside):