Causes
Speaker delays are too great for the Dirac-enabled device to handle, breaking phase.
If a certain speaker, usually a subwoofer (caused by DSP or physical distance), has a great delay (>20ms), some Dirac-enabled devices cannot adjust the other speakers to match this delay. You can check impulse response (timing) data in the Filter Design stage of Dirac Live
Disable any DSP or phase adjustments that could negatively impact response time.
Move the speakers closer together to minimize delay due to physical distance.
Remeasure your listening space with Dirac Live when you have minimized delays.