I reinstalled my browser and logged in to my firefox account. A few hours later I received an email that I should login on multiple accounts to sync (I do not understand why I got this message since I'm already logged in on multiple computers). But the most strange thing is that I received this email on an old email address, one that I do not use anymore for a few years and one I have changed some years ago in my firefox account. It's also not my secondary email address in the account. How is it possible you still use this email address? Do you keep old addresses even after I change it?