Socket.io connection from ReactJS is not being redirected by nginx as any other

I have a React web App which uses axios to communicate with the backend API. Backend receives all requests from suffix /api address. And after that, those are redirected by nginx to localhost:1337 where my backend listens to requests. Everything works okay but the socket connection. The console says it can not find domain/socket.io/... but it should be domain/api/socket.io/.... My connection in the client code:

const ENDPOINT = "https://sinavhukuk.com/api";
const socket = io(ENDPOINT);

Would mention that Strapi is used as a backend service (NodeJS).
Here is /etc/nginx/sites-available/default file configuration.

server {
    # Listen HTTP
    listen 80;
    server_name sinavhukuk.com www.sinavhukuk.com;

    # Redirect HTTP to HTTPS
    return 301 https://$host$request_uri;
}

server {
    # Listen HTTPS
    listen 443 ssl;
    server_name sinavhukuk.com www.sinavhukuk.com;

    # SSL config
    ssl_certificate /etc/letsencrypt/live/sinavhukuk.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/sinavhukuk.com/privkey.pem;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_prefer_server_ciphers on;
    ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';

    # Static Root
    location / {
        proxy_pass http://localhost:3000;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Server $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_set_header Host $http_host;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_pass_request_headers on;
    }
    # Strapi API and Admin
    location /api/ {
        rewrite ^/api/(.*)$ /$1 break;
        proxy_pass http://localhost:1337;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Server $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_set_header Host $http_host;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_pass_request_headers on;
    }
}

It is responsible for redirecting /api/...s to localhost:1337. But on socket it is not completely redirected. The error I get is:

https://sinavhukuk.com/socket.io/..... is not found

As I said, if the nginx worked here as always, it should be

https://sinavhukuk.com/api/socket.io/.....

What am I doing wrong?

EDIT: Added redirection from /socket.io/ to /api/socket.io/ manually, but still redirection happens to /socket.io/ instead of /api/socket.io/

# Socket.io
    location /socket.io/ {
        proxy_pass http://localhost:3000/api/socket.io/;
    }