Can't start cygsshd service

[cygwin@kosowsky.org]

I just installed Cygwin and cygwin sshd on a fresh Win10 Virtual Box
machine.

Running 'ssh-host-config' worked perfectly, saying the service was
installed.
I accepted all the defaults.

However, the service fails to start -- whether on 'reboot' or
manually.

Specifically,
    #cygrunsrv -S cygsshd
    cygrunsrv: Error starting a service: StartService:  Win32 error
    1053:
    The service did not respond to the start or control request in a
    timely fashion

    #net start cygsshd
    The service is not responding to the control function.

    More help is available by typing NET HELPMSG 2186.

I am using the native Windows Defender firewall, which has
"Cygwin SSHD - 22 - Private" enabled for 'Private' (but not for
'Public')

Googling the error messages didn't show anything helpful

Any ideas what might be going wrong here?