This is not the FireBrick you're looking for.
You probably reached this page while trying to access your FireBrick configuration pages.
This means your internet access is not going via your FireBrick, or your FireBrick's LAN stealth address has been changed. You should carefully check IP addresses, etc.
It is also possible that this is a cached page in your browser. Try reloading, and also setting your browser cache settings to check every time.
If your FireBrick LAN stealth address has been changed you can access the FireBrick using the IP it has been changed to. The default setting is 217.169.0.1, should you wish to reset it.