Access to XMLHttpRequest at '' from origin '' has been blocked by CORS policy: Response to preflight request doesn't pass access control check

Both backend and api and frontend are deployed on netlify.
Backend website :
Frontend website :

backend code : GitHub - shetty-nithin/socialife_backend: social network website
frontend code : GitHub - shetty-nithin/socialife_frontend: social networking website

When im trying to login, im getting this CORS issue,

Please help me.

this is my api folder structure :

this is my frontend folder structure :

Simply create a rewrite proxy to bypass CORS: Rewrites and proxies | Netlify Docs

Exmple: netlify-file-browser/netlify.toml at v2 · Hrishikesh-K/netlify-file-browser · GitHub