When your Galaxkey subscription license expires, your identity is no longer valid for doing various Galaxkey operations. When the license expires you can not do following things
1. Open a Galaxkey Secured file.
2. Open a Galaxkey Secured email
3. Synchronise and share files using Galaxkey for Windows
4. Login to your Galaxkey mobile device application.
You can however continue sending secured emails to other Galaxkey users from Outlook Addin.
You will be able to resume complete functionality once the subscription is paid for.