Nginx and dockerfile for SSR

[ting-dev-coder]

Hi, I am front-end. I once used SSR and it deployed successfully.
Now, for the project, I use SSR again but the server page returns 502 gateway
Here is my related doc
dockerfile

FROM node:16.20.2-alpine as build-stage

ARG VUE_APP_SERVICE

WORKDIR /app
COPY package*.json ./

RUN npm install -g @quasar/cli && npm install

COPY . .

ENV VUE_APP_SERVICE="${VUE_APP_SERVICE}"

RUN quasar build -m ssr

FROM node:16.20.2-alpine as production-stage

WORKDIR /usr/share/www

COPY --from=build-stage /app/dist/ssr ./
COPY --from=build-stage /app/package*.json ./

RUN npm i -g pm2@latest
RUN npm install

EXPOSE 9600

# Run SSR application using PM2
CMD ["pm2-runtime", "index.js"]

nginx.conf

user nginx;
worker_processes auto;
pid /run/nginx.pid;
events {
    worker_connections 1024;
    multi_accept on;
    use epoll;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    server {
        listen 9600;
        charset utf-8;
        server_name localhost;
        index      index.html;
        root    /usr/share/nginx/html;

        location / {
            index  index.html index.htm;
            try_files $uri $uri/ /index.html;
        }

        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

    }
}

I am not sure whether the backend set up any other configuration for nginx, but that's all the settings in my project I can see.
please help me out!