Chrome console cohort builder error

apiHelper.js:48 POST http://localhost:8080/openmrs/ws/rest/v1/reportingrest/adhocquery?v=full 500 (Internal Server Error)
send	@	apiHelper.js:48
post	@	apiHelper.js:66
(anonymous)	@	tabsComponent.jsx:47
search	@	tabsComponent.jsx:46
handleSubmit	@	observationComponent.jsx:97
invokeGuardedCallback	@	ReactErrorUtils.js:24
executeDispatch	@	EventPluginUtils.js:83
executeDispatchesInOrder	@	EventPluginUtils.js:106
executeDispatchesAndRelease	@	EventPluginHub.js:41
executeDispatchesAndReleaseTopLevel	@	EventPluginHub.js:52
forEachAccumulated	@	forEachAccumulated.js:22
processEventQueue	@	EventPluginHub.js:252
runEventQueueInBatch	@	ReactEventEmitterMixin.js:15
handleTopLevel	@	ReactEventEmitterMixin.js:25
handleTopLevelImpl	@	ReactEventListener.js:70
perform	@	Transaction.js:141
batchedUpdates	@	ReactDefaultBatchingStrategy.js:60
batchedUpdates	@	ReactUpdates.js:95
dispatchEvent	@	ReactEventListener.js:145