Express proxy server not working (no backend knowledge)

Hi,
I have made a express proxy server to hide the api keys by following online tutorial. Please note, I have no knowledge of backend programming. It worked locally on port 5000 but I wanted to test it by uploading the project on vercel. It threw a 404 error on vercel.

The frontend project is supposed to get coordinates using geolocation web API and then use third party APIs to get user’s address and the weather in their area.

RIght now I only worked on making the URLs work so I am just focusing on one div that is supposed to show the address.

locally it successfully showed the weather and the address.

Can anyone help me?

https://vercel-trial-swart.vercel.app/