Dockerfile in client - important nuance! If you see an nginx web page instead of React App

[hazartilirot]

In case you're wondering I use the latest version of everything up to date. As an example I wrote my code utilizing async/await, functional component against of class component. The code would be available in one of my repos. I cannot explain the reason causing the behaviour if a previous deployment allowed to use multi stage builds in one file - I had no issues with the previous project. This one is just doesn't want to copy files from the build/ directory and I don't know how to trace a reason. Logs didn't show any sign of an error.

**--from=0** this command says copy artifacts from <dir> to <dir>

FROM node:16.13.1-alpine
WORKDIR /app
COPY ["package*.json", "./"]
RUN npm install
COPY . .
RUN npm run build

FROM nginx:1.21.5-alpine
EXPOSE 3000
COPY --from=0 /app/build /usr/share/nginx/html
COPY ./nginx/default.conf ./etc/nginx/conf.d/default.conf

If you're interested, here is my repo.