Issue with this plugin and woocommerce email

Hello, the plugin works great, but in the email that the client receives, there is an error that appears before the Order number and table, how can i fix that?

Warning: call_user_func_array() expects parameter 1 to be a valid callback, class ‘WC_Order’ does not have a method ’email_instructions’ in /home/xxxx/public_html/xxxxxx.com/wp-includes/class-wp-hook.php on line 288