"Cannot GET /" - Error when running a MERN Application (MongoDB, Express, React, Node.js)

I’ve successfully imported a Webapplication I wrote from Github, with the backend (api) and the frontend (client) as two components.

The build and the run part were successfull acccording to DigitalOcean, however when I try to access the App I get the error “Cannot GET /”. And in the headers I see Status Code 404: Not Found. So something is definitely not correctly configured.

Some information about my configuration:

a) Backend

For the backend I used the custom build command yarn build:digitalocean that I’ve defined in my package.json file in the api folder as follows "scripts": {"build:digitalocean": "yarn cache clean && yarn install --production=false && rm -rf node_modules && yarn install --production --frozen-lockfile"}, and the run command for the back end is node index.js.

b) Frontend

The frontend build command is yarn build which is defined in the package.json in the client folder like the following: "scripts": {"build": "vite build",...}, and the run command is npx serve -s dist with dist as the folder name for the built files, specified in vite.config.js as follows:

import { defineConfig } from 'vite'; import react from '@vitejs/plugin-react'; and export default defineConfig({plugins: [react()], build: { outDir: 'dist',},})

Runtime Logs

a) Backend

Server running on port 4000

b) Frontend

(node:18) [DEP0040] DeprecationWarning: The 'punycode' module is deprecated. Please use a userland alternative instead. (Use 'node --trace-deprecation ...' to show where the warning was created) INFO Accepting connections at http://localhost:8080

==> I get the same warning in development as well but the app runs completely fine locally despite this warning.

RUN IN DEV MODE

On my local machine I can easily run both backend and frontend with the following commands:

backend: yarn dev

frontend: nodemon index.js

In the App I also connect to the external Atlas MongoDB, but I do not think that this is the issue here - but maybe it is. For sure I need to adapt certain settings in order to make it run all fine but I expected that at least I would get an error message that would help me further.

What could be the issue? Any help would be very much appreciated!

A question that just came into my mind: If I included my .env file with my ENV variables in the git repository (which I have…), will the Environment Variables in the App Configuration on DigitalOcean overwrite these values if the keys are equal? I hope this is the case…