Also have a look here 7.8 Error Messages.

Error MessageReasonSolution
com.advendio.mediacloud.adServer.adswizz.restServices.utils.AdsWizzException: 400 - constraint.violated: The request entity had the following errors: (Errors: Zones may not be empty (zoneIds); )There are no Zones defined for the Item you are trying to submit

Please define, which Zones should be used for the Item.

You can do this by connecting Zones to the Ad Spec: 3.2.1 Create Ad Spec, Ad Price, and link to AdServer

Or via Inventory Targeting on the Campaign Item: Inventory Targeting

Afterwards, try to submit the Item to AdsWizz again