If a plugin settings save fails, the plugin now shows the reason. Bulk saves are also split so they usually fit within a typical max_input_vars limit.

If a notice still mentions max_input_vars, increase it to at least 3000 on the host. The max_input_vars limit can be configured in your .htaccess, php.ini or wp-config.php file.

Here are 3 ways you can do it:

.htaccess

php_value max_input_vars 3000

php.ini

max_input_vars = 3000

wp-config.php

@ini_set( 'max_input_vars' , 3000 );