WEB Playback SDK Demo app doesn't work in build version

[seymayneym]

Plan

Premium

Country

Turkey

Device

Acer Nitro 5 AN515-57

Operating System

Windows 11

My Question or Issue

I was trying to build an Fake UI for Spotify. First i created the ui and added interactivity using React.js. In production version, started using "npm run dev", app works fine without an issue. But i want to migrate to CEF for desktop environment so i need to use Build version. But when i use "npm run build", "serve -s build" commands add the necessary line:

app.use(express.static(path.join(__dirname, '../build')));

with importing path module. When i try to log in to my Spotify Account via app i get an error "INVALID_CLIENT, Invalid client". I attached backend code -same with the guide- and the WebPlayback.jsx file also i attached my app's Redirect URI's.