Licensing & payments · Licence status and offline use
What does the "Working offline" licence notice mean?
Short answer: Storage Studio couldn't reach the licence server for a while and is using your saved licence. Keep working; reconnecting clears it.
It means Storage Studio hasn't been able to reach the licence server for longer than its offline window, so it's using the licence saved on your Mac. You can keep working — nothing is locked.
Reconnect to the internet when you can; the next successful check-in clears the notice. If you're online and it persists, a firewall or VPN may be blocking the check — try another network.