The old F-Secure Internet Security (FSIS) has been discontinued and you need to first migrate your subscription to F-Secure TOTAL.
Create an account on the website
https://my.f-secure.com Once you finish the registration you need to
contact our support team mentioning the issue and also the following information:
1. The old F-Secure Internet Security (FSIS) subscription key
2. The expiration date it had
3. The email address you used to create the F-Secure TOTAL account