Virtual Machine UEFI Secure Boot Platform Key is out of date. Refer KB 423893.VM Secure boot alarms are enabled from vSphere 9.1.1.0 onwards. To update the Platform Key, VM Hardware version should be minimum version 14. However, License Server deployed in older versions before 9.1.1.0 has Hardware Version 13, hence the Platform Key is not getting updated on License Server.
This alert is not critical and has no impact on the boot or the functionalities of the license server. License Server Hardware version is upgraded to Version 14 from 9.1.1.0 new deployments.
From the vSphere Client, upgrade the compatibility of the license server VM to ESXi 6.7 and later by following the Upgrade the Compatibility of a Virtual Machine Manually procedure.
This issue is documented in the License Server Known Issues section in 9.1.1.0 Release Notes.