I was trying to deploy my mern stack website using render . When I was deploying my backend repository , I am facing a port error,

I deployed my backend, repo so it gave me the backend link. I replaced all the ‘localhost:4000’ where 4000 is my port, with the backend link.

I tested the backend by running my frontend locally but it didn’t work.

It was an ecommerce website in which the products are retreived from mongoDb through the backend folder.
**I had seperated the project into three repositories, one with admin panel, one with frontend and one with backend.
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I deployed the backend repo first then It gave me the link for backend. Then as I mentioned before I put the link In my frontend project. But if it worked , the frontend website would have shown all the products it retreived from the backend. But the frontend is not showing the products which means something is going wrong.

I can’t figure out what is causing the issue, as my backend has no .env file which I had not added in evironment variables. As far as the mongoDB connection goes, the mongoDB link is already linked through the index.js file in the backend repo.

source repo