ems sync error

info: INFO: request.POST: {}
info: INFO: ==========Start syncing ProductCategory(1) via Establishment(4), push all mode is False==========
info: INFO: Fields configurations: {1: {'fields': ('subcategories',), 'subcategories': {1: {'fields': ('products',), 'products': {1: {'fields': None}}}}}}
info: INFO: ==========Finish syncing==========
error: ERROR: Encountered Error: 3b65f62 - /Users/linas/code/revel/Python-Backends/revelV2/core/syncer/syncer.py:111:get_sync_kwargs:u'Values of sync_on field "%s" mustn\'t be empty. Please reconfigure syncer.' % field
error: ERROR: Internal Server ERROR: /resources/OrderAllInOne/
Traceback (most recent call last):
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/base.py", line 372, in wrapper
    response = callback(request, *args, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/tastypie/resources.py", line 433, in dispatch_list
    return self.dispatch('list', request, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 263, in dispatch
    return super(WrapperResource, self).dispatch(request_type, request, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/tastypie/resources.py", line 465, in dispatch
    response = method(request, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 282, in post_list
    response = self._post_list_unsafe(request, data, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 349, in _post_list_unsafe
    top_items = self._save_subitems(AllInOneOrderItemResource(), request, dataitems, order_uri, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 505, in _save_subitems
    response = self._save_object(resource, request, datadict, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 592, in _save_object
    response = resource.post_list(request, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 170, in post_list
    return super(WrapperResource, self).post_list(request, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/tastypie/resources.py", line 1343, in post_list
    updated_bundle = self.obj_create(bundle, **self.remove_api_resource_names(kwargs))
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/ordering.py", line 472, in obj_create
    bundle = super(OrderItemResource, self).obj_create(bundle, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 140, in obj_create
    return self.save(bundle)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 455, in save
    bundle.obj.save()
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/models/ordering_order.py", line 1250, in save
    super(OrderItem, self).save(*args, **kwargs)
  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/django/db/models/base.py", line 589, in save
    force_update=force_update, update_fields=update_fields)
  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/django/db/models/base.py", line 626, in save_base
    update_fields=update_fields, raw=raw, using=using)
  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/django/dispatch/dispatcher.py", line 198, in send
    response = receiver(signal=self, sender=sender, **named)
  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/receivers.py", line 115, in on_orderitem_post_save_handle_returns
    'PRODUCTCATEGORY_SYNC'
  File "/Users/linas/code/revel/Python-Backends/revelV2/core/syncer/link.py", line 84, in get_sync_obj_for_syncing
    qs_filter_kwargs=qs_filter_kwargs
  File "/Users/linas/code/revel/Python-Backends/revelV2/core/syncer/syncer.py", line 121, in get_sync_obj
    kwargs.update(get_sync_kwargs(obj, sync_on, create=create))
  File "/Users/linas/code/revel/Python-Backends/revelV2/core/syncer/syncer.py", line 111, in get_sync_kwargs
    u'Values of sync_on field "%s" mustn\'t be empty. Please reconfigure syncer.' % field
ImproperlyConfigured: Values of sync_on field "lock_uuid" mustn't be empty. Please reconfigure syncer.
warn: WARNING: Internal Server Error: {'message': u'Your request could not be processed', 'traceback': 'Traceback (most recent call last):\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/base.py", line 372, in wrapper\n    response = callback(request, *args, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/tastypie/resources.py", line 433, in dispatch_list\n    return self.dispatch(\'list\', request, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 263, in dispatch\n    return super(WrapperResource, self).dispatch(request_type, request, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/tastypie/resources.py", line 465, in dispatch\n    response = method(request, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 282, in post_list\n    response = self._post_list_unsafe(request, data, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 349, in _post_list_unsafe\n    top_items = self._save_subitems(AllInOneOrderItemResource(), request, dataitems, order_uri, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 505, in _save_subitems\n    response = self._save_object(resource, request, datadict, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/allinone.py", line 592, in _save_object\n    response = resource.post_list(request, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 170, in post_list\n    return super(WrapperResource, self).post_list(request, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/tastypie/resources.py", line 1343, in post_list\n    updated_bundle = self.obj_create(bundle, **self.remove_api_resource_names(kwargs))\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resources/ordering.py", line 472, in obj_create\n    bundle = super(OrderItemResource, self).obj_create(bundle, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 140, in obj_create\n    return self.save(bundle)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/api/resource_wrappers.py", line 455, in save\n    bundle.obj.save()\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/models/ordering_order.py", line 1250, in save\n    super(OrderItem, self).save(*args, **kwargs)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/django/db/models/base.py", line 589, in save\n    force_update=force_update, update_fields=update_fields)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/django/db/models/base.py", line 626, in save_base\n    update_fields=update_fields, raw=raw, using=using)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/env/lib/python2.7/site-packages/django/dispatch/dispatcher.py", line 198, in send\n    response = receiver(signal=self, sender=sender, **named)\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/coreApi/receivers.py", line 115, in on_orderitem_post_save_handle_returns\n    \'PRODUCTCATEGORY_SYNC\'\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/core/syncer/link.py", line 84, in get_sync_obj_for_syncing\n    qs_filter_kwargs=qs_filter_kwargs\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/core/syncer/syncer.py", line 121, in get_sync_obj\n    kwargs.update(get_sync_kwargs(obj, sync_on, create=create))\n\n  File "/Users/linas/code/revel/Python-Backends/revelV2/core/syncer/syncer.py", line 111, in get_sync_kwargs\n    u\'Values of sync_on field "%s" mustn\\\'t be empty. Please reconfigure syncer.\' % field\n\nImproperlyConfigured: Values of sync_on field "lock_uuid" mustn\'t be empty. Please reconfigure syncer.\n', 'sei_diagnostic_code': '3b65f62'}