Unable to connect to server through domain name

Hi guys hope you doing well
I’m working on setting up Parse Dashboard for my application, and I want to use a custom domain name with Cloudflare’s Full Strict SSL for enhanced security. however I got

Server not reachable: unable to connect to server

through domain name consider if I change - PARSE_SERVER_URL and - PARSE_DASHBOARD_SERVER_URL values to ip address everything works fine through ip address and this issue only persist with domain name

this is my docker-compose.yml :

version: '3'
services:

    mongo:
        image: mongo
        ports:
            - 27017:27017
        volumes:
            - ./data-db:/data/db

    parse:
        image: parseplatform/parse-server
        ports:
            - 1337:1337
        links:
            - mongo
        environment:
            - PARSE_SERVER_APPLICATION_ID=xxxxxxxxxxxxxxx
            - PARSE_SERVER_MASTER_KEY=xxxxxxxxxxxxxxx
            - PARSE_SERVER_DATABASE_URI=mongodb://mongo:27017/dev
            - PARSE_SERVER_START_LIVE_QUERY_SERVER=1
            - PARSE_SERVER_LIVE_QUERY={"classNames":["people","monitor"]}
            - PARSE_SERVER_MASTER_KEY_IPS=0.0.0.0/0
            - PARSE_SERVER_URL=https://example.com
            - PARSE_SERVER_MOUNT_PATH=/parse
          

    dashboard:
        image: parseplatform/parse-dashboard
        ports:
            - 4040:4040
        depends_on:
            - parse
        environment:
            - PARSE_DASHBOARD_SERVER_URL=https://example.com
            - PARSE_DASHBOARD_APP_ID=xxxxxxxxxxxxxxx
            - PARSE_DASHBOARD_MASTER_KEY=xxxxxxxxxxxxxxx
            - PARSE_DASHBOARD_APP_NAME=MyApp
            - PARSE_DASHBOARD_ALLOW_INSECURE_HTTP=0
            - PARSE_DASHBOARD_USER_ID=admin
            - PARSE_DASHBOARD_USER_PASSWORD=admin
            

and this is my nginx config file :

server {
    listen 80;
    server_name example.com www.example.com;
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl;
    server_name example.com www.example.com;

    ssl_certificate /etc/nginx/ssl/example.com.pem;
    ssl_certificate_key /etc/nginx/ssl/example.com.key;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384';
    ssl_prefer_server_ciphers on;

    location / {
        proxy_pass http://localhost:1337/parse;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }
}

server {
    listen 443 ssl;
    server_name dash.example.com

    ssl_certificate /etc/nginx/ssl/example.com.pem;
    ssl_certificate_key /etc/nginx/ssl/example.com.key;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers 'ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384';
    ssl_prefer_server_ciphers on;

    location / {
        proxy_pass http://localhost:4040;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
        
    }
}