Klipper error

Most of the wiring is done, aside from the hotend unit, and trying to get the motors up and running. However, when Klipper starts, I am getting the following error message:

Unable to read tmc uart 'stepper_x' register IFCNT Once the underlying issue is corrected, use the "RESTART" command to reload the config and restart the host software. Printer is halted

The klippy.log is currently displaying this (amongst many other lines of similar error):

TMC init error

Traceback (most recent call last):
File "/home/pi/klipper/klippy/extras/tmc.py", line 120, in _handle_connect
self._init_registers()
File "/home/pi/klipper/klippy/extras/tmc.py", line 105, in _init_registers
self.mcu_tmc.set_register(reg_name, val, print_time)
File "/home/pi/klipper/klippy/extras/tmc_uart.py", line 221, in set_register
self.ifcnt = ifcnt = self._do_get_register("IFCNT")
File "/home/pi/klipper/klippy/extras/tmc_uart.py", line 209, in _do_get_register
"Unable to read tmc uart '%s' register %s" % (self.name, reg_name))
CommandError: Unable to read tmc uart 'stepper_x' register IFCNT

From the plethora of Internet search, it appears that this is not an uncommon problem. But because I am using odd hardware combinations, I am not having much success in finding a cure. Presently, the main board is the BTT SKR-Pro v1.2 including the EXP board to allow for the full 7 drivers, each with the TMC2209 drivers. 

Have checked that the MOTOR POW is at 24v, and switched the various stepstick and no improvement. Also confirmed that the jumpers are as per the manual. Measured the voltage at the VDD pin, 3.3V and at the VM pin, 24v. So the drivers are being correctly powered. 

The debugging continues...

See below photo of the current setup, with one stepstick removed...