500 Internal Server Error

Hi I am trying to keep the profile URL pretty using htaccess. But when I go to the link which is this profile/30/about after I did the code with htaccess to make it pretty it will give me a 500 internal server error when I type this link profile/30/about but when I do like this profile?30&about it will work fine with no issues.

This is my htaccess code

// this is the block to make the file with no php extension

RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^([^.]+)$ $1.php [NC]

// this is the rewrite url to make it pretty

RewriteRule ^/?profile/(\d+)$ /profile.php?$1 [QSD,L] RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME}.php -f RewriteRule ^(.*)$ $1.php [QSA,L]