Just to clarify your wiring for one motor from your previous post -
KFlop JP7 -> Motor
15 (Step) -> 3 (Input A+)
16 (Dir) -> 4 (Enable +)
23 (5V) -> 4 (Enable +)
25(GND) -> (Enable -)
I'm guessing Dir going to Enable is a typo, and should be 2 (Input B+)?
In that case you need to connect 6 (Input B-) and 7 (Input A-) to Gnd. That's unless these drives have some additional circuitry where you don't need to connect the - terminals when not running differential signals.
Digital Ground, is a way of describing ground for low power circuits. Any grounds going to your drives control circuitry can be described as a digital ground, whereas the ground/0V for providing the main power for the drive, would typically be described as a power ground.
However, having just found a manual for the drives -
https://www.teknic.com/files/downloa...ser_manual.pdf
I think you may need to wire them a bit differently. Connect 5V to 3 (Input A+) and 2 (Input B+), then connect 7 (Input A-) to 16 (dir), and 6 (Input B-) to 15 (step), and choose the correct number to run channel/axis0 using Open Collector mode. (Going by the step/dir mode info on page 101, you have your inputs mixed up)
If you look at page 38 of the manual, and the NPN/Sinking *Open Collector* diagram, that's how you should be connecting things up, as that will give a higher voltage at the drive inputs, than the current LVTTL method you're using.
Regarding homing, are there any messages appearing in the console?
Personally, I'd disable all the limit switches until you have motion, as it removes one potential problem.