This guide will help in solving the error in the title
The error appears when you try to "reinstall" F-secure on a computer. The following F-secure guide will show how to fix this:
To remove computers from the blacklist
Log in to PSB Portal.
Open the Subscriptions tab (on the company level).
Click the Clear list of removed computers button on the right side of the subscription key. This releases all blacklisted computers tied to that specific subscription key.
If you need to return the computers to the subscription they were removed from, go to the company subscription view and clear the list of removed computers for this subscription.
If you need to add the removed computers again, you can add them under another subscription key.
If you are reinstalling the PSB WKS or PSB ESS software, you do not need to remove the computer from the account.