My app is not working, WHY?

Provide a screenshot of the error.
I highly doubt it says this, it likely says that you can get help here.

Netlify is largely “self service”, you’re supposed to read documentation to solve your own problems.

If your error is “Page not found”, read this Support Guide:
https://answers.netlify.com/t/support-guide-i-ve-deployed-my-site-but-i-still-see-page-not-found/125