On Twitter player card preview tool i m getting HTTP status code 406


when I test http://ec2-54-225-196-43.compute-1.amazonaws.com/twitter.php on preview tool its working fine without any error.

But when I have rewrite rule in .htaccess like this
RewriteRule ^/twitter$ twitter.php [NC,L]

Now this url (http://ec2-54-225-196-43.compute-1.amazonaws.com/twitter ) showing HTTP status code 406

Can any body help me to get it out from this issue?