AngularJS w/Prerender 404 error on home page - angularjs

Question

All of my angularjs site works with prerender except for the home page. When crawled, it sends back a 404 page. I have reason to believe it is this line of code in my .htaccess file, RewriteRule ^(.*)$ http://service.prerender.io/https://%{HTTP_HOST}/$1 [P,L] but I am not sure.
<IfModule mod_rewrite.c>
RewriteEngine On
# If requested resource exists as a file or directory
# (REQUEST_FILENAME is only relative in virtualhost context, so not usable)
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -f [OR]
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -d
# Go to it as is
RewriteRule ^ - [L]
# If non existent
# If path ends with / and is not just a single /, redirect to without the trailing /
RewriteCond %{REQUEST_URI} ^.*/$
RewriteCond %{REQUEST_URI} !^/$
RewriteRule ^(.*)/$ $1 [R,QSA,L]
# Handle Prerender.io
RequestHeader set X-Prerender-Token "notprovidingthiscode"
RewriteCond %{HTTP_USER_AGENT} baiduspider|facebookexternalhit|twitterbot|rogerbot|linkedinbot|embedly|quora\ link\ preview|showyoubot|outbrain|pinterest [NC,OR]
RewriteCond %{QUERY_STRING} _escaped_fragment_
# Proxy the request
RewriteRule ^(.*)$ http://service.prerender.io/https://%{HTTP_HOST}/$1 [P,L]
# If non existent
# Accept everything on index.html
RewriteRule ^ /index.html

Answer 1

The issue turned out to be that the .htaccess file was serving example.com/index.html rather than just example.com when accessing the root of the angularjs app. That in turn didn't play well with ui-router because the $stateProvider doesn't serve filenames at the end of urls without being explicit. Accessing example.com/index.html did indeed cause my page to throw a 404 error $urlRouterProvider.otherwise('404');
Adding the following code fixed my issue.
$urlRouterProvider.when('/index.html', '/');
This redirects example.com/index.html to example.com which points to the correct rendering in prerender.io.