If you see "Not Found" error while directly browsing to a specific path, For eg: https://yourdomain.com/something , this might be helpfull (ReactJS):
In your public folder (folder which contains index.html) create a file called _redirects with no extension. Then, type the following inside it:
/* /index.html 200
Now save, commit, push and publish. :)
Reason for "Not Found" is because, when using router eg: React Router it handles all the routes but when you directly goto an endpoint, netlify must know where to redirect you. That is what we are specifying in the _redirects file.