Unable to make API Calls to backend(Node js) from frontend(reactjs)

Hi Team,

We have developed app frontend as React js which has a URL of https://localhost:3000 and node on https://localhost:4000, as per documentation we have configured nginx reverse proxy as below in file path: /etc/nginx/sites-available/default

location / {
        proxy_pass http://localhost:3000;
        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;
    }

location / app2 {
        proxy_pass http://localhost:4000;
        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;
    }

so when we make an api calls to node js from react.

example

axios.get('https://localhost:4000/app2/sparters')
.then(res => console.log(res.data))

we are getting error as below : GET http://localhost:4000/app2/spartners 404 not found

Kindly assist on this issue to fix it as soon as possible , so are we doing something wrong or some thing is missing here.

Thanks and Regards, Shivaprasad.G