Error message is shown

Error message is shown, and I can not push submit button.

Warning: Undefined array key “restriction_to” in /wp-content/plugins/wp-user-frontend/includes/fields/class-field-textarea.php on line 92

Please tell me how to solve it?

WordPress ver: 6.0.3

WP User Frontend ver: 3.5.29

<?php

/**
  * Textarea Field Class
  */
class WPUF_Form_Field_Textarea extends WPUF_Field_Contract {

    public function __construct() {
        $this->name       = __( 'Textarea', 'wp-user-frontend' );
        $this->input_type = 'textarea_field';
        $this->icon       = 'paragraph';
    }

     /**
      * Render the Textarea field
      *
      * @param array  $field_settings
      * @param int    $form_id
      * @param string $type
      * @param int    $post_id
      *
      * @return void
      */
    public function render( $field_settings, $form_id, $type = 'post', $post_id = null ) {
        if ( isset( $post_id ) && $post_id != '0' ) {
            if ( $this->is_meta( $field_settings ) ) {
                $value = $this->get_meta( $post_id, $field_settings['name'], $type );
            }
        } else {
            $value = $field_settings['default'];
        }

        $req_class   = ( $field_settings['required'] == 'yes' ) ? 'required' : 'rich-editor';
        $textarea_id = $field_settings['name'] ? $field_settings['name'] . '_' . $form_id : 'textarea_';

        $this->field_print_label( $field_settings, $form_id ); ?>

             <?php if ( in_array( $field_settings['rich'], [ 'yes', 'teeny' ] ) ) { ?>
                <div class="wpuf-fields wpuf-rich-validation <?php printf( 'wpuf_%s_%s', esc_attr( $field_settings['name'] ), esc_attr( $form_id ) ); ?>" data-type="rich" data-required="<?php echo esc_attr( $field_settings['required'] ); ?>" data-id="<?php echo esc_attr( $field_settings['name'] ) . '_' . esc_attr( $form_id ); ?>" data-name="<?php echo esc_attr( $field_settings['name'] ); ?>">
            <?php } else { ?>
                <div class="wpuf-fields">
            <?php } ?>

                <?php
                    $tinymce_settings = wpuf_filter_editor_toolbar( $field_settings );

                if ( ( $field_settings['rich'] === 'teeny' || $field_settings['rich'] === 'yes' ) ) {
                    $editor_settings = [
                        'textarea_rows' => $field_settings['rows'],
                        'quicktags'     => false,
                        'media_buttons' => false,
                        'editor_class'  => $req_class,
                        'textarea_name' => $field_settings['name'],
                    ];

                    if ( ! empty( $tinymce_settings ) ) {
                        $editor_settings['tinymce'] = $tinymce_settings;
                    }

                    if ( $field_settings['rich'] === 'teeny' ) {
                        $editor_settings['teeny'] = true;
                    }

                    $editor_settings = apply_filters( 'wpuf_textarea_editor_args', $editor_settings );
                    wp_editor( $value, $textarea_id, $editor_settings );
                } else {
                    ?>
                    <textarea
                        class="textareafield <?php echo esc_attr( ' wpuf_' . $field_settings['name'] . '_' . $form_id ); ?>"
                        id="<?php echo esc_attr( $field_settings['name'] . '_' . $form_id ); ?>"
                        name="<?php echo esc_attr( $field_settings['name'] ); ?>"
                        data-required="<?php echo esc_attr( $field_settings['required'] ); ?>"
                        data-type="textarea"
                        placeholder="<?php echo esc_attr( $field_settings['placeholder'] ); ?>"
                        rows="<?php echo esc_attr( $field_settings['rows'] ); ?>"
                        cols="<?php echo esc_attr( $field_settings['cols'] ); ?>"
                    ><?php echo esc_textarea( $value ); ?></textarea>
                    <span class="wpuf-wordlimit-message wpuf-help"></span>

                        <?php
                }
                ?>

                 <?php
                    $this->help_text( $field_settings );
                    if ( isset( $field_settings['content_restriction'] ) && $field_settings['content_restriction'] ) {
                                $this->check_content_restriction_func(
                                    $field_settings['content_restriction'],
                                    ! empty( $field_settings['rich'] ) ? $field_settings['rich'] : 'no',
                                    $field_settings['name'] . '_' . $form_id,
                                    $field_settings['restriction_type'],
                                    $field_settings['restriction_to']
                                );
                    }
                    ?>

         <?php
            $this->after_field_print_label();
    }

     /**
      * Get field options setting
      *
      * @return array
      */
    public function get_options_settings() {
        $default_options      = $this->get_default_option_settings();
        $default_text_options = $this->get_default_textarea_option_settings();

        return array_merge( $default_options, $default_text_options );
    }

     /**
      * Get the field props
      *
      * @return array
      */
    public function get_field_props() {
        $defaults = $this->default_attributes();
        $props    = [
            'input_type'        => 'textarea',
            'label'             => __( 'Textarea', 'wp-user-frontend' ),
            'is_meta'           => 'yes',
            'rows'              => 5,
            'cols'              => 25,
            'rich'              => 'no',
            'id'                => 0,
            'is_new'            => true,
            'show_in_post'      => 'yes',
            'hide_field_label'  => 'no',
            'restriction_type'  => 'character',
            'restriction_to'   => 'max',
            'text_editor_control' => [],
        ];

        return array_merge( $defaults, $props );
    }

     /**
      * Prepare entry
      *
      * @param $field
      *
      * @return mixed
      */
    public function prepare_entry( $field ) {
        check_ajax_referer( 'wpuf_form_add' );

        $field = isset( $_POST[ $field['name'] ] ) ? sanitize_text_field( wp_unslash( $_POST[ $field['name'] ] ) ) : '';
        return trim( $field );
    }

     /**
      * Render textarea field data
      *
      * @since 3.3.0
      *
      * @param mixed $data
      * @param array $field
      *
      * @return string
      */
    public function render_field_data( $data, $field ) {
        $data      = implode( ',', $data );
        $hide_label = isset( $field['hide_field_label'] )
           ? wpuf_validate_boolean( $field['hide_field_label'] )
           : false;

        if ( empty( $data ) ) {
            return '';
        }

        $container_classnames = [ 'wpuf-field-data', 'wpuf-field-data-' . $this->input_type ];

        ob_start();
        ?>
            <li class="<?php echo esc_attr( implode( ' ', $container_classnames ) ); ?>">
               <?php if ( ! $hide_label ) : ?>
                    <label><?php echo esc_html( $field['label'] ); ?>:</label>
                <?php endif; ?>
               <?php echo wp_kses_post( wpautop( make_clickable( $data ) ) ); ?>
            </li>
         <?php
            return ob_get_clean();
    }

     /**
      * Sanitize field data
      *
      * @since 3.3.1
      *
      * @param string $data
      * @param array  $field
      *
      * @return string
      */
    public function sanitize_field_data( $data, $field ) {
        return wp_kses_post( $data );
    }
}

The page I need help with: [log in to see the link]