I tried deploying my backend to Heroku and after I did that my website was still working on http://localhost:3000/
but after I build the app for deployment on GitHub Pages the website stopped working on the Github page but works on the local environment.
this is my GitHub repo: https://github.com/pranjalchaplot/missedmessage/
My deployed GitHub Page (doesn't work): https://pranjalchaplot.github.io/missedmessage/