Need to know what all devices have been activated with particular license

Hi Team,
Is there a way where we can know what all devices have been activated with a particular parallels license key? I have a license with 4 devices enabled. But actively we are using on two devices only. When we try to activate its saying the limit has reached. So we want to know on what all devices we have been using the license key.

Let me know if we have a way to check this.