This error message appears when you deactivate your device from your account at personal.f-secure.com. To resolve this, please reinstall F-Secure Mobile Security.
First, uninstall F-Secure Mobile Security: Go to Settings > Applications > F-Secure Mobile Security > Uninstall.
Then re-download F-Secure Mobile Security from the Google Play Store. When you are activating the F-Secure Mobile Security app please make sure to log in as an existing user by selecting 'Already have an account? Log in here' and your account credentials.
If you were not able to reinstall F-Secure Mobile Security with the above steps, F-Secure Mobile Security is preloaded on your device. To reset F-Secure Mobile Security click here.