Docker build on remote VPS fails pulling base image through a local proxy (connection refused 127.0.0.1:7897)

Problem

docker build or docker pull on a machine fails because the Docker daemon inherited HTTP_PROXY pointing to a local proxy that is no longer running.

Error (redacted / normalized)

failed to solve: failed to fetch oauth token: Post "https://auth.docker.io/token": proxyconnect tcp: dial tcp 127.0.0.1:7897: connect: connection refused

Applies when

Docker Desktop / dockerd with HTTP_PROXY/HTTPS_PROXY env (e.g. Clash on 7897) that was later stopped

Root cause

The daemon keeps the proxy env from when it started; with the proxy down every registry call fails.

Fix

1. Check docker info | grep -i proxy.
2. Either start the proxy again, or remove the proxy from Docker settings (Desktop: Settings → Resources → Proxies) / /etc/systemd/system/docker.service.d/http-proxy.conf and restart dockerd.
3. Retry the pull.

How to verify

docker pull hello-world succeeds.

What did not work

--network host on build; unsetting the shell env (daemon has its own).

Risks

None.