Issue re Bronze challenge

#1

I added a .htaccess file to the chattrbox folder:

ErrorDocument 404 /app/404.html

and added a 404.html file to the /app/chattrbox folder:

<h1>Nooooooo!</h1>

but my 404.html file is not displayed when I enter a non-existent file name. I’m using Chrome 74.0.3729.108. If I go to localhost(3000)/404.html the page displays properly
is .htaccess no longer the accepted way to redirect to a custom 404 page?

Thanks!

[ETA I’ve done chmod 0755 .htaccess but this made no difference]