UM()->form()->add_error( ) not working

Hello Champ Camba! I using Ultimate Member plugin, this is the best membership plugin, thanks for the Ultimate Member team.

I want to add the google recaptcha v2 invisible captcha to the default login form, and this this my code:

<?php

//add recaptcha invisible script to UM login form
add_action( 'um_after_form', array($this, 'my_recaptcha_invisible_script'), 10, 1);

function my_recaptcha_invisible_script($args){

    $mode = $args['mode'];

    if( $mode == 'login' ){
        $html = '';
        ob_start(); ?>
                <script>
                    //add a class to the form element
                    var addFormClass = document.querySelectorAll(".um-login form");
                        
                        addFormClass[0].classList.add("um-login-recaptcha-invisible");
                
                </script>

                <script src="https://www.google.com/recaptcha/api.js" async defer></script>

                <script>
                   function onSubmit(token) {
                     document.getElementsByClassName("um-login-recaptcha-invisible")[0].submit();
                   }
                </script>

                <script>
                    //add site key and class to the form submit button
                    var Inputs = document.querySelectorAll(".um-login-recaptcha-invisible input");
                    
                    for( var i = 0; i < Inputs.length; i++ ) {
                        
                        if( Inputs[i].type.toLowerCase() == 'submit' ) {
                            Inputs[i].classList.add('g-recaptcha');
                            Inputs[i].setAttribute('data-sitekey', 'xxxxxx');
                            Inputs[i].setAttribute('data-callback', 'onSubmit');
                        }
                    }
                </script>
                <input type="hidden" name="my_recaptcha_um_error" id="my_recaptcha_um_error" value="true" data-key="my_recaptcha_um_error" />
        <?php $html = ob_get_contents();
        ob_end_clean();
        
        echo $html;

         //Show error msg
        if ( $mode == 'login' && UM()->fields()->is_error( 'my_recaptcha_um_error' ) ) {
            echo UM()->fields()->field_error( UM()->fields()->show_error( 'my_recaptcha_um_error' ) );
        }
    }
}

//Verify user submit
add_action( 'um_submit_form_errors_hook_login', array($this, 'my_recaptcha_um_login_verification'), 10, 1 );
function my_recaptcha_um_login_verification(){
    $mode = $args['mode'];
    if( $mode == 'login'){
        $response  = isset( $_POST['g-recaptcha-response'] ) && !empty( $_POST['g-recaptcha-response'] ) ? sanitize_text_field( $_POST['g-recaptcha-response'] ) : '';

        $v2_invisible_secretkey   = 'xxxx';

        $remoteip       = esc_textarea( $_SERVER['REMOTE_ADDR'] );

        $verify_url     = 'https://www.recaptcha.net/recaptcha/api/siteverify';

        $args_array = $verify_url . '?secret=' . $v2_invisible_secretkey . '&response=' . $response . '&remoteip=' . $remoteip;

        $response_json = wp_remote_post( $args_array );
        
        $obj_json = wp_remote_retrieve_body( $response_json );
        
        $result = json_decode($obj_json, true);

        //I use print_r() to print the result and google return the json normally
        echo '<pre>';
        print_r($result);
        echo '</pre>';

        /* print_r result

            Array
            (
                [success] => 1
                [challenge_ts] => 2022-01-04T02:26:54Z
                [hostname] => 192.168.9.168
            )

        */

        
        if( isset($result['success']) && $result['success'] == "1" ){
            //if success nothing need to do
        }else{
            //add this error since not work 
            UM()->form()->add_error( 'my_recaptcha_um_error', __('ERROR:  Captcha verification failed, please try again!!!') );
        }

        //even I change the code like this , when user click submit , still login success, not show the error msg and not stop the user to login
        if( isset($result['success']) && $result['success'] == "1" ){                        }
            //This error still not work
            UM()->form()->add_error( 'my_recaptcha_um_error', __('ERROR:  Captcha verification failed, please try again!!!') );
        }
    }
}

Could you tell me where is the problem ?