The PFHostID is a unique identifier for your server hardware that acts as a security key. When you activate an entitlement, it ties that entitlement to your server using the PFHostID.
PFHostIDs are generated using the MAC address of your server's primary network interface controller. If you change your server's network configuration after activating your entitlement, or are trying to run the PFBucketd server daemon on a virtual machine that has not been correctly configured to provide a static MAC address, this will cause your PFHostID to change to a different value or may mean the PFHostID cannot be determined at all.
If this happens, your entitlements will no longer be available to use. To avoid any problems, ensure that the MAC address of your server's primary interface controller is not changed after activating your entitlements.