CORS issue with NGinx and fetch react native

I'm facing a cors issue only with web browser when I want to implement a react native app. Alhough I've configured

Access-Control-Allow-Origin: *

I'm still getting a CORS error from the browser. Is there anything that I'm missing?

client:

return fetch(newURL, {
    method: "GET",
    credentials: 'include',
    headers: {
        'Authorization': 'Bearer ' + accessToken,
        'Content-Type': 'application/json'
    },
})

server nginx:

       location / {
            proxy_set_header X-Forwarded-Host $host;
            proxy_set_header X-Forwarded-Server $host;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            add_header 'allow' 'GET';
            add_header 'access-control-allow-origin' '*';
            add_header 'access-control-allow-credentials' 'true';
            add_header 'access-control-expose-headers' 'filename';

            proxy_pass http://127.0.0.1:9000/;
    }

}

interaction

The query is failing because of preflights with CORS. Here is the msg

Access to fetch at 'xxxx/access/verif?email=xxxx&v=0.1&1733744786626' from origin 'localhost:19006' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

Any clue?

Thanks!

The problem was that because I'm using spring boot, OPTIONS http method was not handled properly. Additionally because I provide a Bearer, CORS restrictions don't support wildcard.

Here is my Nginx working configuration, you might need to add some http methods according to your needs.

 location / {
            proxy_set_header X-Forwarded-Host $host;
            proxy_set_header X-Forwarded-Server $host;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

            if ($request_method = OPTIONS) {
               add_header Access-Control-Allow-Origin $http_origin ;
               add_header Access-Control-Allow-Credentials 'true' ;
               add_header Access-Control-Allow-Methods 'GET, POST, OPTIONS';
               add_header Access-Control-Allow-Headers 'content-type,authorization';
               add_header Content-Type text/plain;
               add_header Content-Length 0;
               return 204;
            }
            add_header Access-Control-Allow-Origin $http_origin;
            add_header Access-Control-Allow-Methods 'GET, POST, OPTIONS';
            add_header Access-Control-Allow-Credentials 'true' ;
            add_header Access-Control-Allow-Headers 'content-type,authorization';


            proxy_hide_header "X-Frame-Options";

            proxy_pass http://127.0.0.1:9000/;
    }