Critical Error, site crashed

I bought the plugin for Woocommerce. So far everything works. In the plugin documentation it says that it is compatible with Woocommerce order status manager, but there is a critical bug or malfunction. After installing and activating it the status manager the website still works, but when I try to edit the email for the new order status I created, the whole website stopped working and I received a critical error email, caused by WP HTML mail:

WordPress versión 5.5.3)
Plugin actual: WP HTML Mail – WooCommerce (versión 2.9.7)
PHP versión 7.2.28

Detalles del error
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Se ha producido un error del tipo E_ERROR en la línea 56 del archivo /home/admin/web/public_html/wp-content/plugins/wp-html-mail-woocommerce/includes/class-addon-order-status-manager.php. Mensaje de error: Uncaught Error: Call to undefined function wc_order_status_manager() in /home/admin/web/public_html/wp-content/plugins/wp-html-mail-woocommerce/includes/class-addon-order-status-manager.php:56
Stack trace:
#0 /home/admin/web/public_html/wp-content/plugins/wp-html-mail-woocommerce/includes/class-addon-order-status-manager.php(71): WPHTMLMail_WooCommerce_AddOn_OrderStatusManager->get_emails()
#1 /home/admin/web/public_html/wp-includes/class-wp-hook.php(287): WPHTMLMail_WooCommerce_AddOn_OrderStatusManager->activate_mailbuilder_for_order_status_emails(Array)
#2 /home/admin/web/public_html/wp-includes/plugin.php(206): WP_Hook->apply_filters(Array, Array)
#3 /home/admin/web/public_html/wp-content/plugins/wp-html-mail-woocommerce/includes/class-wphtmlmail-woocommerce.php(140): apply_filters(‘haet_mail_suppo…’, Array)
#4 /home/admin/web/public_html/wp-content/plugins/wp-html-mail-woocommerce/includes/class-wphtmlmail-woocommerce.ph