Have you tried "burping" the master?
If not;
Put the bike on the center stand or Pit stand, remove the reservoir cap, turn the handle bars all the way to the left (your trying to get the master tilted down toward the banjo fitting) this will allow air to bubble up into the reservoir by pumping VERY LIGHTLY on the lever (I've had best results with only slight movements of the lever, (not a full squeeze). Once you have got all the bubbles out you can with it tilted to the left, then tilt it to the right & repeat. Continue this process left & right till you can no longer get any bubbles; By then you should start to feel some lever response and can now go to the bleeding the Calipers.