Im trying to redirect on Error 500 , but its not happening.

.htaccess file

  ErrorDocument 500 /custom.php

custom.php just has a

  echo '<h1>ERROR OCCURED </h1>';

should I configure httpd.conf ? is there anything else that Im missing

my httpd.conf

     Alias /error/ "/var/www/error/"

      <IfModule mod_negotiation.c>
       <IfModule mod_include.c>
    <Directory "/var/www/error">
    AllowOverride all
    Options IncludesNoExec
    AddOutputFilter Includes html
    AddHandler type-map var
    Order allow,deny
    Allow from all
    LanguagePriority en es de fr
    ForceLanguagePriority Prefer Fallback
</Directory>