When Quantize MIDI it stops playing back

Something strange happened here, i had this once, I record something with my controller to an instrument track, and when i quantize it, either the region or the track via real time properties, the track stopped playing back the midi data!



I have pro tools 10.3.8, 10.9.3 3.5 Ghz intel core i7 iMac with 8 GB of ram



Anyone help!?