Nuxt app don't work correctly in my docker container on VPS

I have a Nuxtjs app with nginx that running via docker-compose on VPS and it was running ok on 80 port and I could access it with my domain but only with HTTP.

So I needed to install SSL-certificates with certbot and I tried a lot to follow many different tutorials.

I already asked a question about it here and I was advised to read this Medium tutorial. So I did everything as said and it's worked, now I have redirect from http to htttps even if I try to reach my app not through domain but directly via IP address.

But the page is Bad Gateway on https://example.com. But I can reach my app if I go on http://example.com:3000, so I think I messed up with nginx configs.

Here is my files:

• My Dockerfile:

    FROM node:12.18.3-alpine
    
    RUN mkdir -p /usr/src/nuxt-app
    WORKDIR /usr/src/nuxt-app
    
    RUN apk update && apk upgrade
    RUN apk add git
    
    COPY . /usr/src/nuxt-app/
    RUN npm install
    
    RUN npm run build
    
    EXPOSE 80
    
    ENV NUXT_HOST=0.0.0.0
    ENV NUXT_PORT=3000
    
    CMD [ "npm", "start" ]

• My docker-compose.yml:

    version: "3"
    services:
      nginx:
        image: nginx:1.15-alpine
        ports:
          - "80:80"
          - "443:443"
        volumes:
          - ./data/nginx:/etc/nginx/conf.d
          - ./data/certbot/conf:/etc/letsencrypt
          - ./data/certbot/www:/var/www/certbot
        command: '/bin/sh -c ''while :; do sleep 6h & wait $${!}; nginx -s reload; done & nginx -g "daemon off;"'''
      certbot:
        image: certbot/certbot
        volumes:
          - ./data/certbot/conf:/etc/letsencrypt
          - ./data/certbot/www:/var/www/certbot
        entrypoint: "/bin/sh -c 'trap exit TERM; while :; do certbot renew; sleep 12h & wait $${!}; done;'"
      nuxt:
        image: sda2000den/agency:0.4 #<--- my nuxt app
        container_name: nuxt_app
        ports:
          - "3000:3000"

• And finally my nginx config file:

    server {  
        root /var/www;
        listen 80;
        server_name studioagnc.com;
        gzip on;
        gzip_types  text/plain application/xml text/css application/javascript;
        gzip_min_length 1000;
        location / {
            proxy_pass http://127.0.0.1:3000;
        }
        location /.well-known/acme-challenge/ {
            root /var/www/certbot;
        }
    }
    server {
        listen 443 ssl;
        server_name studioagnc.com;
        
        ssl_certificate /etc/letsencrypt/live/studioagnc.com/fullchain.pem;
        ssl_certificate_key /etc/letsencrypt/live/studioagnc.com/privkey.pem;
        include /etc/letsencrypt/options-ssl-nginx.conf;
        ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
    
        location / {
            proxy_pass http://studioagnc.com; #for demo purposes
        }
    }

I'm not really friendly with nginx and I do not fully understand what this config does. What can I do to make it work properly?