On Facebook the "token" may expire in three ways:
- Time: generally after 60 days from the last access the token gets deactivated.
- Change password: the token is linked to the old password, if you change it is necessary to log in again with the new password.
- Other problems: We can turn off your token if this is causing problems to the site.
To reauthorize Facebook just login to your site, click on Social Networks and re-connect the expired social.