The email says:
QuoteIf you are looking to unsubscribe from receiving such security announcements on [email address] in the future, please login to our community and set your preference on this URL: http://www.simplemachines.org/community/index.php?action=profile;area=notification
That URL goes to the main profile page, with nothing about notifications.
How
do I unsubscribe from security update notifications? (I'm no longer supporting a SMF forum.) I couldn't find it anywhere.
Thanks!
When I click on that link I'm taken to a page that has a check box next to what say, "Receive forum newsletters, announcements and important notifications by email.".
I'm logged in too.
I am also taken to the right place.
To answer your immediate question: you can just go to the notifications area from your profile (it's in the second menu) - you can even click the link in your post if you like.
To answer the wider question of why it didn't work... that's very likely your email client being confused at the ; in the URL and dropping the rest of it (several clients do that)