thank you for your super fast response.
Indeed , the issue was the usb cable was dislodged enough on the PC side that it prevented communication to the Kemper.
Pushing it back in so that it was fully seated on the jack made it work properly again.
It seems that Kemper Editor does know that there is something wrong since it programmatically disables the menu item:
"load into editor and preview" so perhaps displaying some sort of status warning to the user that there's no communication with the Kemper would be a nice feature.