How to use proxy_pass for simplest IP mapping?

Basically whenever anyone visit http://123.123.123.123/sample, I wish to reverse proxy map to http://456.456.456.456:7001/sample

My attempt on nginx config as below

server {
    listen 80 default_server;
    server_name _;

    location / {
        proxy_pass http://456.456.456.456:7001;
    }
}

However the traffic doesnt seems to be able to be routed successfully?