There can be several reasons why recipients may label your transactional e-mail as unwanted, and each reason requires appropriate follow-up. For almost all transactional e-mails, the recipient expects to receive an e-mail and will even take action if the e-mail is not received in the mailbox in the foreseeable future. And yet, it happens that transactional emails received result in complaints. What drives the recipient to press the 'SPAM' button? For transactional e-mail, a complaint rate above 0.03% is cause for concern and requires attention and action.
Fear of commercial follow-up emails
For starters, a recipient may want to avoid the possibility that more commercial emails will follow after that essential transactional email is received. Thus, the recipient indicates that further "emails" are undesirable. The recipient does not realize that future transactional emails will then also not be sent. For example, in the case of repeat purchases, order confirmations are not sent. From that point of view, following up on these complaints is essential.
For example, have customer service contact the recipient in question and reassure the recipient. Then ask the recipient to drag the 'unwanted' e-mail back from the junk mail folder to the inbox. This signals to the ISP that the e-mail was mistakenly labeled as 'junk'. You can then remove the recipient from the filter list in Flowmailer, and future transactional emails will be sent again to the recipient.
Your transactional email is too commercial
Transactional communication is necessary communication and then especially necessary for the recipient. It goes without saying that a transactional e-mail can be commercial. However, if you go overboard with this, it will irrevocably affect the number of complaints. Make sure the ratio service message/marketing message complies with the 80/20 rule and make sure your marketing message is relevant and consistent with your transactional message. You will notice that this approach will rarely result in complaints.
Whoopsie!
Finally, a recipient may have unintentionally pressed the 'SPAM' button. Such complaints in themselves will not result in a too high complaint rate. However, it is important to follow up on these complaints, as described earlier.