I am using an SMTP app server to send bulk emails by following guidelines and providing an unsubscribe feature by setting the List-Unsubscribe-Post and List-Unsubscribe headers. In the emails I receive, I can see the unsubscribe button in both Gmail web and the Mac/iPhone Mail app, and I successfully unsubscribed.

However, when sending an emails with a different subject and content, but from the same email address, the unsubscribe button does not appear in the Mac/iPhone Mail app but appear in Gmail. Could you please provide any guidance or suggestions to resolve this issue? Thank you.

Gmail:

Mac mail app

I conducted some research, particularly within the Apple community, but unfortunately did not find a solution. Any assistance you provide would be very helpful, thanks.

Expectation:

Gmail: The emails I send should always have an unsubscribe button. If a specific email is unsubscribed, the rest of the emails should still display the unsubscribe button.

Mac Mail app/iPhone: Currently, once an email is unsubscribed, the unsubscribe button no longer appears for any other emails. I would like this button to remain available for all emails.