Domain API Gateway error TypeError: NetworkError when attempting to fetch resource. in wso2am 4.3.0

I just completed config nginx for domain gateway wso2am But I tested the request on its demo, it reported an error as shown in the picture

“TypeError: NetworkError when attempting to fetch resource.”

upstream domain.com.vn {
     least_conn;
     server 10.0.x.x:8280 max_fails=3 fail_timeout=30s;
    server 10.0.x.x:8280 max_fails=3 fail_timeout=30s;
 }

server {
    listen     80;
    server_name domain.com.vn;
    return 301 https://$host$request_uri;



    location = /basic_status {
                stub_status;
                allow 127.0.0.1;
                allow ::1;
                allow 10.2.15.87;
                deny all;
        }

    }



server {
    listen 443 ssl;
    server_name domain.com.vn;

    ssl_certificate /etc/nginx/ssl/2023/ ....crt;
    ssl_certificate_key /etc/nginx/ssl/2023/....key;

    access_log /var/log/nginx/domain.com.vn_access.log;
    error_log /var/log/nginx/domain.com.vn_error.log debug;

    location / {
        proxy_pass http://domain.com.vn;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_connect_timeout 60;
        proxy_send_timeout 60;
        proxy_read_timeout 60;
        proxy_set_header Authorization $http_authorization;

        proxy_buffering off;
        proxy_redirect off;


    }

}

Please help me with the problem, I thank you very much

Can you try renaming the upstream to something that is not a dns name? NGINX might be trying to resolve it as a DNS name in the proxy_pass directive, which would cause an issue as it would be proxying traffic back to itself.

hmm I think DNS does not have any problems , because I checked domain gateway and seen it is work normal

I see that DNS works as expected, but I have a feeling what is happening is that instead of routing traffic to the upstream group defined in the config, NGINX thinks it is routing to a DNS name. if you change the upstream group name to domain-com-vn instead of domain.com.vn, and update the proxy_pass directive to match, do you see the same behavior?