That is live data from VRS. The data is coming from local dump1090-fa installation.
Piaware is the part which delivers data to Flightaware.
Very likely that your local dump1090-fa is running, but the piaware service has been stopped.
You need to SSH into your Raspberry and check the status of the Piaware Service with
sudo systemctl status piaware
It should return something similar like this: Active: active (running) since Thu 2020-11-19 14:17:22 CET; 3 days ago
if this is not the case, (re)start the service with
sudo systemctl restart piaware
and verify it afterwards again with the command above.
If this is not working, try it with restarting your device. If still not working, follow the instructions to get piaware installed again (see Step 2 in the install documentation):
If you log into FA and go to the sites stats page. Go to the settings page (select the little paddle wheel).
You can restart the Pi or just PiAware without needing to be on the local network.