This message means that a valid Corona license was not found. Please see the general Corona activation articles:
3ds Max:
Cinema 4D:
Possible causes:
- License has not been activated yet
- License was removed
- License was activated, but then the computer was left without Internet connection for too long
- License file was deleted
- Subscription is canceled
- Hardware configuration changed
Solutions:
Activate Corona - see article links for specific Corona versions and host platforms above.