htaccess Rewriterule [P] 404

im running angular js on my main domain and running prerender node for seo caching.

the problem is i keep on getting 404 on this

<ifmodule mod_rewrite.c=""> RewriteEngine On Options +FollowSymLinks All

    RewriteCond %{HTTP_USER_AGENT} Googlebot|bingbot|Googlebot-Mobile|Baiduspider|Yahoo|YahooSeeker|DoCoMo|Twitterbot|TweetmemeBot|Twikle|Netseer|Daumoa|SeznamBot|Ezooms|MSNBot|Exabot|MJ12bot|sogou\sspider|YandexBot|bitlybot|ia_archiver|proximic|spbot|ChangeDetection|NaverBot|MetaJobBot|magpie-crawler|Genieo\sWeb\sfilter|Qualidator.com\sBot|Woko|Vagabondo|360Spider|ExB\sLanguage\sCrawler|AddThis.com|aiHitBot|Spinn3r|BingPreview|GrapeshotCrawler|CareerBot|ZumBot|ShopWiki|bixocrawler|uMBot|sistrix|linkdexbot|AhrefsBot|archive.org_bot|SeoCheckBot|TurnitinBot|VoilaBot|SearchmetricsBot|Butterfly|Yahoo!|Plukkie|yacybot|trendictionbot|UASlinkChecker|Blekkobot|Wotbox|YioopBot|meanpathbot|TinEye|LuminateBot|FyberSpider|Infohelfer|linkdex.com|Curious\sGeorge|Fetch-Guess|ichiro|MojeekBot|SBSearch|WebThumbnail|socialbm_bot|SemrushBot|Vedma|alexa\ssite\saudit|SEOkicks-Robot|Browsershots|BLEXBot|woriobot|AMZNKAssocBot|Speedy|oBot|HostTracker|OpenWebSpider|WBSearchBot|FacebookExternalHit [NC,OR]
    RewriteCond %{QUERY_STRING} ^(.*_escaped_fragment_=.*)

    <IfModule mod_proxy_http.c>
    RewriteRule ^(.*)$ http://prerender.em0xi0nx.com/http://%{HTTP_HOST}%{REQUEST_URI}? [P,L]
 </IfModule>

</ifmodule>

when im using this RewriteRule ^(.*)$ http://prerender.em0xi0nx.com/http://%{HTTP_HOST}%{REQUEST_URI}? [P,L]

i keep on getting 404 on [P] it it keeps on saying /panel/ not found on my url http://example.com/panel/

but if i change it to [R] its working. i dont really know the problem but while searching this whole day they said its the mod_proxy. i dont really know..

please help me..