OK, so the MOB is a generic view of some APIs, and the APIs are the core of the communications- so not all APIs will appear in the MOB. Is that correct?

I added the code to refresh the services view on the vCenter so that changes to the services are now reflecting on the vCenter Services section of the hosts' web GUI. However, some hosts are showing this error when the code runs:

Get-View : Cannot validate argument on parameter 'VIObject'. The argument is null or empty. Provide an argument that is not null or empty, and then try the command again.
At C:\Users\jmilano\Documents\PowerShell_Scripts\Vulnerabilities\Remove-Vuln_2023-02.ps1:157 char:20
+ ...  = Get-View (Get-VMHost $ESXiHostName).ExtensionData.ConfigManager.Se ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidData: (:) [Get-View], ParameterBindingValidationException
    + FullyQualifiedErrorId : ParameterArgumentValidationError,VMware.VimAutomation.ViCore.Cmdlets.Commands.DotNetInterop.GetVIView

You cannot call a method on a null-valued expression.
At C:\Users\jmilano\Documents\PowerShell_Scripts\Vulnerabilities\Remove-Vuln_2023-02.ps1:158 char:5
+     $ss.RefreshServices()
+     ~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

The error happens when this command is executed:

$ss = Get-View (Get-VMHost 192.168.30.5).ExtensionData.ConfigManager.ServiceSystem

Thanks for your help so far.