99 is a little low, but they should still hatch (temp should be 99.5-100). Are these Coturnix quail? If so, 30% humidity seems to be about ideal until hatch. Then the humidity should go up to 50-60%.
If you are trusting the readings on your incubator, I can just about guarantee that the...
The first thing you want to do is make sure that the incubator is as clean as you can get it. Candle the remaining eggs and get rid of any dead ones.
A few questions:
What temperature are you incubating at? Don't trust your incubator's readings. If you don't already have calibrated...