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

问题

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.

报错原文（已脱敏/规范化）

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

适用环境

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

根因

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

修复步骤

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.

如何验证

docker pull hello-world succeeds.

试过没用的办法

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

风险提示

None.