Connecting WPforms to php code using code snippet

Hello, I want to connect the result of form, to pass it to an API, and then display the result of the API. In order to do this, I have a 3 steps plan :

1. Create a form with WPforms and note its ID
2. Write the php code with the snippet plugin code that gather WP form data, make an api call and display it
3. Instantiate the WPform on my page, and paste in the following block the snippet code so that it is evaluated

First, for testing purpose I only want to display the result of the form so I wrote the following code :

function be_crm_display_raw_form_data( $fields, $entry, $form_data, $entry_id ) {
    echo "<pre>";
    print_r( $fields );
    echo "</pre>";
}
add_action( 'wpforms_process_complete', 'be_crm_display_raw_form_data', 10, 4 );

But after filling the form on preview page and hitting submit, nothing shows up. Can you please point to me what I am doing wrong.

Thanks in advance for your answer