Where can I change the max_input_vars default value. I am using bluehost server
You can change the default value of max_input_vars via htaccess
php_value max_input_vars 2000
if you got 500 error, you should use following
<IfModule mod_php5.c> php_value max_input_vars 2000 </IfModule>
More methods can be checked by following link
How to Increase max_input_vars