Why does Sitecore 9.1.1 Prerequisites EnableWindowsOptionalFeature fail?

Question

I am trying to run the prerequisites.json file for a SC 9.1.1 install and I am getting the following error:

[----------------------------------------------------------------------------------- WindowsFeatures : EnableWindowsOptionalFeature ----------------------------------------------------------------------]
VERBOSE: Target Image Version 10.0.14393.3022

Install-SitecoreConfiguration : The source files could not be found. 
Use the "Source" option to specify the location of the files that are required to restore the feature. For more information on specifying a source location, see 
http://go.microsoft.com/fwlink/?LinkId=243077.

At line:1 char:1
+ Install-SitecoreConfiguration -Path .\Prerequisites.json -Verbose
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,Install-SitecoreConfiguration

[TIME] 00:00:19

Enable-WindowsOptionalFeature : The source files could not be found. 
Use the "Source" option to specify the location of the files that are required to restore the feature. For more information on specifying a source location, see 
http://go.microsoft.com/fwlink/?LinkId=243077.
At C:\Program Files\WindowsPowerShell\Modules\SitecoreInstallFramework\2.1.0\Public\Install-SitecoreConfiguration.ps1:641 char:25
+                         & $entry.Task.Command @paramSet | Out-Default
+                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Enable-WindowsOptionalFeature], COMException
    + FullyQualifiedErrorId : Microsoft.Dism.Commands.EnableWindowsOptionalFeatureCommand

Answer 1

Apparently the problem here had to do with installing the .NET Framework 3.5. We simply mounted the Windows Server ISO and manually installed the .NET Framework 3.5. Then we tried running the Prerequisites.json file again and it worked.