adding custom form-tag

Hi,

I read your docs about adding custom form tag.
https://contactform7.com/2015/01/10/adding-a-custom-form-tag/

However, it not works.

I have custom post type of business.
On every page there is a contact form.

I want to pass the title of the business.
I am using [_post_title] but it not always work – and this tag not exported to csv by flamingo.

So, I want to get the custom post type’ title – and get it as [hidden] tag.
Because I don’t need to show it to user.

I made this code:

add_action( 'wpcf7_init', 'custom_add_form_tag' );
 
function custom_add_form_tag() {
  wpcf7_add_form_tag( 'posttitle', 'custom_form_tag_handler' );
}
 
function custom_form_tag_handler( $tag ) {
  return the_title();
}

This doesn’t work.

Can you help please?