Please create a .htaccess file inside the public folder with the following code:
# General Apache options
AddHandler fcgid-script .fcgi
AddHandler cgi-script .cgi
#Options +FollowSymLinks +ExecCGI
# If you don't want Rails to look in certain directories,
# use the following rewrite rules so that Apache won't rewrite certain requests
#
# Example:
# RewriteCond %{REQUEST_URI} ^/notrails.*
# RewriteRule .* - [L]
# Redirect all requests not available on the filesystem to Rails
# By default the cgi dispatcher is used which is very slow
#
# For better performance replace the dispatcher with the fastcgi one
#
# Example:
# RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]
RewriteEngine On
# If your Rails application is accessed via an Alias directive,
# then you MUST also set the RewriteBase in this htaccess file.
#
# Example:
# Alias /myrailsapp /path/to/myrailsapp/public
# RewriteBase /myrailsapp
RewriteBase /
RewriteRule ^$ index.html [QSA]
RewriteRule ^([^.]+)$ $1.html [QSA]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]
# In case Rails experiences terminal errors
# Instead of displaying this message you can supply a file here which will be rendered instead
#
# Example:
# ErrorDocument 500 /500.html
ErrorDocument 500 "<h2>Application error</h2>Rails application failed to start properly"
This should fix the 404 error.