Your subscription is no longer valid. It expired a few days ago. JFBConnect will continue to work. However, the auto configuration tool inside of JFBConnect (Autotune) where you're seeing this method is only for active subscribers as well. If you need to change your Facebook application setup, you will need to do so manually through the Facebook Developer area, instead of Autotune. If the warning is the only issue that you're seeing, it is safe to ignore.
As stated on the
JFBConnect purchase page
Our extensions will continue working after your subscription expires. Once expired, you will lose access to new releases, support and the use of our auto-configuration tools.
Let us know if you have any questions.
-Melissa