Failed to send email to customer

Hi, I’m using this plugin to send the tracking code to customer via email. However, customers cannot receive the email. And I found my debug file and saw the error code like below:

[14-Sep-2022 09:03:12 UTC] PHP Fatal error:  Uncaught Error: Class 'wcast_partial_shipped_customizer_email' not found in /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/themes/porto-child/woocommerce/emails/customer-partial-shipped-order.php:21
Stack trace:
#0 /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/plugins/woocommerce/includes/wc-core-functions.php(345): include()
#1 /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/plugins/woocommerce/includes/wc-core-functions.php(364): wc_get_template()
#2 /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/plugins/woo-advanced-shipment-tracking/includes/emails/class-shipment-partial-shipped-email.php(112): wc_get_template_html()
#3 /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/plugins/woocommerce/includes/emails/class-wc-email.php(567): WC_Email_Customer_Partial_Shipped_Order->get_content_html()
#4 /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/plugins/woo-advanced-shi in /home/hencestudi/domains/hencestudio.com/public_html/staging/wp-content/themes/porto-child/woocommerce/emails/customer-partial-shipped-order.php on line 21

And the email customizer also display “There has been a critical error on this website.”

Anyway to solve this problem?