Npm安装在Docker容器中找不到我的自定义注册表

我正在尝试使用docker-compose在node：alpine图像上构建一个React应用。但是，当时间到了时，npm install它不会出现以下错误：

npm ERR! code ENOTFOUND
npm ERR! errno ENOTFOUND
npm ERR! network request to https://<myCustomRegistry>/packageName failed, reason: getaddrinfo ENOTFOUND <myCustomRegistry>
npm ERR! network This is a problem related to network connectivity.
npm ERR! network In most cases you are behind a proxy or have bad network settings.
npm ERR! network 
npm ERR! network If you are behind a proxy, please make sure that the
npm ERR! network 'proxy' config is set properly.  See: 'npm help config'

npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2020-04-03T15_06_13_130Z-debug.log

myCustomRegistry 是我通过vpn访问的注册表的名称。

我试过的

• 重新启动VPN
• 更改.npmrc
• 使用我公司的DNS在正确服务下的docker-compose.yml文件中添加dns字段，该DNS会知道myCustomRegistry。我首先认为这可能是因为docker-compose dns无法识别myCustomRegistry。我可能做错了，这仍然是一个可能的假设。
• 设置一个npm代理（阅读文档，但不知道该怎么做）

文件：

Docker文件

# Builds the react app into 3 static files
FROM node:alpine as builder
WORKDIR /app
COPY . .
RUN npm i && npm run build

# Copies those static files and serve them
FROM node:alpine
RUN yarn global add serve
WORKDIR /app
COPY --from=builder /app/build .
EXPOSE 80
CMD ["serve", "-p", "80", "-s", "."]

Docker-compose配置文件：

version: "3.7"
services:

  <... other services>
  front:
    build: ./front
    container_name: dobby_front
    ports: 
      - "8080:80"
    volumes:
      - './front:/app'
      - '/app/node_modules'
    dns:
      - 10.128.103.16
      - 172.21.103.5

.npmrc

registry=https://<myCustomRegistry>
save-exact=true

提前致谢