No option to de-authorize

I tried to add a book but got the error message "Error! Check Activation". I then learned I had to de-authorize my computer and then re-authorize.

Now, the problem is that the option "Help > Erase Authorization" does not seem to exist. My only options are these [https://cdn1.cdnme.se/4167047/9-3/namnlos_59a1a8419606ee265093b641.jpg] and they do not help with the needed de-authorization.

So how do I de-authorize so that I can read this god forsaken book?