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First off, which phone do you have? Moto Z, Moto Z Droid, or Moto Z Play?
I think you did this already, but if not, use the MDK Display app from the Play Store to verify that the phone is detecting your mod as a Display mod. You can also use the MDK Utility app.
The VID should be 0x00000*312* and the PID should be 0x000*10903*. If those are correct, then the phone thinks it is a Display mod and will automatically download and flash the appropriate firmware.
If these aren't correct, then it's a different problem. However, I assume it is detecting correctly since you get this error: Same error: External display is not connected. You wouldn't get that unless it thought it was a Display mod.
The next step is to make sure that you don't have anything blocking the 16-pins on the rear of the phone and the rear of the MDK. Just double-check that there isn't any gunk, stickers, damage, etc.
If they look good, then triple-check the DIP switches (triple because you already double-checked them for the last reply). For the Display mod, I have:
The DIPs are hard to read and it may not be obvious which is on and which is off. Also, make sure you are looking at A and B from the right orientation.
If you want to take a photo of the DIPs (or the phone and MDK pins), I'd be happy to take a look at them. Either PM them or post them to a site like Imgur.
edit: formatting, always formatting