WSE 2016 cannot back up after Windows 11 upgrade, "Cannot connect to the Windows Server Essentials Client Computer Management Service"

[Quartz]

I've upgraded my 8700 / A770 box to Windows 11. I'm running Windows Server Essentials 2016. But it isn't backing itself up and I'm now getting "Cannot connect to the Windows Server Essentials Client Computer Management Service" when I try and do a manual backup. Further, the server thinks that the PC is offline.

I've tried reinstalling the Connector service and rebooting.

Anything else?

 

[Quartz]

From the Launchpad I also cannot access the shared folders, but if I browse to \\servername then they turn up just fine.