Transactional emails are an essential part of any successful business that requires reliable communication with its customers. However, sending an email does not guarantee that it will reach the intended recipient. This is where transactional email fallback behavior comes into play. Fallback behavior is a strategy that ensures an email is delivered to the recipient, even if the first delivery attempt fails. By having a fallback behavior in place, businesses can avoid losing important messages or having their emails marked as spam.