Psshutdown stopped working on target WIN10 system

[softfoot]

I have been using psshutdown to remotely shut down a variety of systems and it has worked beautifully ... untill recently where it has stopped working on ONE win10 system.

I run the commend "psshutdown -s \sysname" on my win7 system and it works fine on one win10 system but on another in hangs just after :-

"PsShutdown v2.6 - Shutdown, logoff and power manage local and remote systems
Copyright (C) 1999-2023 Mark Russinovich
Sysinternals - www.sysinternals.com"

With no error message, not even a "connecting" message
Both win10 systems are up to date and I'm using v2.6.

What could be the cause ???
Regards,
David