Order cancellation notification is not sent to the customer, what is wrong? (Cancellation with e-mail to the customer)

Activate (checkmark) cancellation mail in the logistics process (in the project)

Check cancellation business letter template (must exist, but created as a template with general text in the standard system)

A standard e-mail address for sending the documents must be available (basic functionality in Basic Settings → E-mail)

(In the order or in the customer address the cancellation notification can be blocked additionally, check the checkmarks here)