This error message appears when you deactivate your device from www.lookout.com. To resolve this, please reinstall Lookout.
First, uninstall Lookout: Go to Settings > Applications > Lookout > Uninstall.
Then re-download Lookout from the Google Play Store. When you are activating the Lookout 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 Lookout with the above steps, Lookout is preloaded on your device. To reset Lookout click here.