BL Touch Stopped Working.

I was five hours into a six hour print and got a 28mm X direction layer shift. No idea what caused it. I stopped the print cleaned the bed and (via Pronterface) went to home the bed (G28). The gantry homed X and Y and then I got the following message:

"Error:Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)
[ERROR] Error:Printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)

Error:!! STOP called because of BLTouch error - restart with M999
[ERROR] Error:!! STOP called because of BLTouch error - restart with M999"

Entering M999 followed by G28 just reproduced the error. I powered down and then checked the BL Touch connections. The white signal wire seemed a bit loose, so I tightened that. All other wires are secure. Powering back up, the BL Touch did not do its normal probe up and down routine. The main red light flickered for about three seconds, it then flashed 7 times and then came on fully. At the end of the flashing, the blue LED on the circuit board also came on. Testing, the black and white signal wires gave a reading of 0.975 K Ohms.

I had homed and levelled the bed (G28, G29) then saved the data (M500) prior to starting to the six hour print print earlier with no problem.

Printer: Hypercube Evolution (CoreXY) with KFB2.0 Board running 24v. Genuine Antclab BL Touch v1.0.

Anybody any idea what has happened?