Sort out Existing Web App

I have a react web app that used to work , now I cant serve, deploy or build, I suspect the plugins are outdated. I need someone to check the app and its conditions and make sure you sort out any issues so I can build and deploy again, I can do my own coding on the changes I require , so please note this project purpose is to check why my react webapp project is having errors ( it worked before, and now has errors without any code changes )