PHP's max_input_vars settings determines how many input variables should be allowed to be passed in the request.
The default value for max_input_vars is set to 1,000 and is usually enough.
The limit can easily be reached if the php developer has created a bulk editing/processing functionality.
This was the case with one of our WordPress plugins which allows people to edit their WordPress media files' attributes such as alt, caption, description called Orbisius Media Property Editor
These snippets should allow you to increase the php's max_input_vars limits.
You will need to add those lines to your .htaccess file.
<IfModule mod_php5.c> php_value max_input_vars 10000 php_value suhosin.post.max_vars 10000 php_value suhosin.request.max_vars 10000 </IfModule> <IfModule mod_php7.c> php_value max_input_vars 10000 php_value suhosin.post.max_vars 10000 php_value suhosin.request.max_vars 10000 </IfModule>
Note: the settings will work for hosting servers that use apache web server.
If the above doesn't work check with your hosting's support if it's possible if they can increase those limits via custom php.ini file.
You can check if the change has worked if you create a temporary php file that calls phpinfo(); function.
Then you can look for max_input_vars value.