after clicking sent on netlify Page Not Found Looks like you've followed a broken link or entered a URL that doesn't exist on this site. code example
Example: Site cannot be accessed broken link or url that doesn’t exist react netlify
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: