OpenSSH Server won't install on Windows 10?

This is Windows 10 Pro build 18363 on a domain. There is no WSUS.

When I have tried installing OpenSSH Server from Optional Features ctrl panel, it takes a long time and sits at 10% progress, fails and no history appears on optional features history.

I tried installing OpenSSH server and client with PowerShell:

Add-WindowsCapability -Online -Name OpenSSH.Client~~~~0.0.1.0

Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0

Client installed ok but Server fails:

PS C:\WINDOWS\system32> Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
Add-WindowsCapability : Add-WindowsCapability failed. Error code = 0x800f0954
At line:1 char:1
+ Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Add-WindowsCapability], COMException
    + FullyQualifiedErrorId : Microsoft.Dism.Commands.AddWindowsCapabilityCommand

. . .

PS C:\Windows\System32\OpenSSH> Get-WindowsCapability -Online | ? Name -like 'OpenSSH*'


Name  : OpenSSH.Client~~~~0.0.1.0
State : Installed

Name  : OpenSSH.Server~~~~0.0.1.0
State : NotPresent

I see that:

If the error 0x800f0954 occurs installing optional Windows features, it may be because the system is unable to access the Windows Update server. This is especially true in case of domain-joined computers which is configured to downloads updates from a WSUS server from https://edulab.unitn.it/tecnici/fix-error-0x800f0954-installing-net-framework-3-5-or-any-optional-feature/#:~:text=If%20the%20error%200x800f0954%20occurs,updates%20from%20a%20WSUS%20server.&text=Restart%20Windows.,you're%20able%20to%20install%20.