How to enable reverce proxy in synology with docker

Question

I am trying to enable reverse proxy manger in Synology with docker i have done all the required steps but not able to enable my service i get "DNS_PROBE_FINISHED_NXDOMAIN" error in every browser right now, I have done the following steps.

1. Created and run the nginx-proxy-manager successfully in Synology Docker container with docker compose

content of my Docker-Compose file for nginx-proxy-manager

  nginx-proxy:
        image: 'jc21/nginx-proxy-manager:latest'
        restart: unless-stopped
        ports:
            - '83:80'
            - '86:81'
            - '4443:443'
        volumes:
            - /volume1/docker/nginx-proxy/data:/data
            - /volume1/docker/nginx-proxy/ssl:/etc/letsencrypt

1. Bought a domain
2. Transferred my domain into Cloudflare
3. Added an A-record in my DNS setting for a subdomain e.g. proxy-manager.example.com and for IP field I used the IP address where my Synology NAS is running
4. Added SSL certificate for my example.com domain in my proxy-manager admin console
5. Created new proxy host and in the IP field I added the same IP address of my Synology NAS and for port I added the port where my service is running
6. Also tried to put the IP address of my docker container in the field of proxy host in nginxproxy-manager admin console with no lick
7. Opened the 81, 80, 443,83,86,and 4443 ports in Synology NAS firewall and also opened the same ports in my router

till now, it seems every thing to be fine, but when I try to access my service with the domain I get the "DNS_PROBE_FINISHED_NXDOMAIN" error in every browser I don't know where in which step I am doing a mistake I would be very happy if someone help me