Unsubscribe link

[Freeman]

Hi everybody, I have a WordPress website and and I use Roundcube to send emails. I was about to start my lauching phase but most of my automated user verification mails and other mails end up considered as spams, blocked and bouncing back under the title "Mail delivery failed :Message returning to sender". What is strange is that sites like mail-tester and others have rated my website 9/10 or 10/10. However the common observation is that since my email lack the Unsubscribe link at the headerthey look spammy.
So can anyone here have an idea how I can solve this please ?

[SKaero]

You would need to find a WordPress plugin that would handle unsubscribes.