This recent email from email@example.com contains "Unsubscribe" (underlined - upper left hand corner):
A click shows a box containing: "Stack Exchange provides a page at meta.stackexchange.com where you can manage your email subscriptions."
The link brings me to meta.stackexchange.com/email/unsubscribe/inbox/2413237/… and it tells me (without any further ado):
You have been unsubscribed You have successfully unsubscribed, you will no longer receive daily updates about your inbox. (This is unnecessarily verbose but an interesting linguistic pattern: passive voice followed by active voice with the same verb.)
To change my SO email settings I can go to https://stackoverflow.com/users/edit/NNNNNNN.
So, where is that page the text in the box refers to? Could it be that the message text is incorrect?