Click on the icon for the identity safe in the upper right corner, then click logout of your Norton account. Then go back to the icon and click it again, and click login to Norton account. Once you log in to your Norton account it will prompt you to log into your vault and it will work. You have to be logged into your Norton account and the vault and I think once it expires, it is too stupid to inform you and it stays logged in and prevents access to the vault.

This is obviously a huge problem and a major oversight on Norton's part. Big surprise there, they don't seem to care about Firefox users. After waiting a year for the identity safe to return, this is a major disappointment. Good thing I still use LastPass. Norton has completely lost my trust.