The license was retrieved less than a month ago
Is there in fact a license in the STARDOG_HOME directory? Could the env var STARDOG_HOME have changed or not been set for some reason. Can you check that it’s set to what you think it is?
it is invoked via
sudo docker run -e STARDOG_EXT="/var/opt/stardog/lib" -v /data/stardog:/var/opt/stardog -p 5820:5820 stardog/stardog
and /data/stardog does have a license.
Your immediate problem can probably be solved by adding the —force flag to the license request to get a new license.
As to why You can try checking the log, did you change the permissions on anything in the /data/Stardog dir? Update the system clock? Set the wrong date on the flux capacitor?