diff --git a/gbpservice/neutron/plugins/ml2plus/drivers/apic_aim/mechanism_driver.py b/gbpservice/neutron/plugins/ml2plus/drivers/apic_aim/mechanism_driver.py
index 1a6fe7857..bd890f6da 100644
--- a/gbpservice/neutron/plugins/ml2plus/drivers/apic_aim/mechanism_driver.py
+++ b/gbpservice/neutron/plugins/ml2plus/drivers/apic_aim/mechanism_driver.py
@@ -4874,16 +4874,28 @@ class ApicMechanismDriver(api_plus.MechanismDriver,
         # REVISIT: Deal with distributed port bindings? Also, consider
         # moving this to the ML2Plus plugin or to a base validation
         # manager, as it is not specific to this mechanism driver.
+        failure_count = 0
+        failure_hosts = set()
         for port_id, in (mgr.actual_session.query(models.PortBinding.port_id).
                         filter(models.PortBinding.host != '',
                                models.PortBinding.vif_type ==
                                portbindings.VIF_TYPE_UNBOUND)):
+            mgr.output("Attempting to bind port %s" % port_id)
             # REVISIT: Use the more efficient get_bound_port_contexts,
             # which is not available in stable/newton?
             pc = self.plugin.get_bound_port_context(
                 mgr.actual_context, port_id)
             if (pc.vif_type == portbindings.VIF_TYPE_BINDING_FAILED or
                 pc.vif_type == portbindings.VIF_TYPE_UNBOUND):
-                mgr.validation_failed(
-                    "unable to bind port %(port)s on host %(host)s" %
+                mgr.bind_ports_failed(
+                    "Unable to bind port %(port)s on host %(host)s" %
                     {'port': port_id, 'host': pc.host})
+                failure_count += 1
+                failure_hosts.add(pc.host)
+        if failure_count:
+            mgr.output(
+                "Failed to bind %s ports on hosts %s. See log for details. "
+                "Make sure L2 agents are alive, and re-run validation to try "
+                "binding them again." % (failure_count, list(failure_hosts)))
+        else:
+            mgr.output("All ports are bound")
diff --git a/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/aim_validation.py b/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/aim_validation.py
index 8ff49f250..e48e0fae7 100644
--- a/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/aim_validation.py
+++ b/gbpservice/neutron/services/grouppolicy/drivers/cisco/apic/aim_validation.py
@@ -122,6 +122,9 @@ class ValidationManager(object):
                     raise RollbackTransaction()
         except RollbackTransaction:
             pass
+        except Exception as exc:
+            self.output("Validation failed with exception: %s" % exc)
+            return api.VALIDATION_FAILED_UNREPAIRABLE
 
         # Bind unbound ports outside transaction.
         if (self.repair and
@@ -225,6 +228,10 @@ class ValidationManager(object):
         self.output("Failed UNREPAIRABLE due to %s" % reason)
         self.result = api.VALIDATION_FAILED_UNREPAIRABLE
 
+    def bind_ports_failed(self, message):
+        self.output(message)
+        self.result = api.VALIDATION_FAILED_BINDING_PORTS
+
     def _validate_aim_resources(self):
         for resource_class in self._expected_aim_resources.keys():
             self._validate_aim_resource_class(resource_class)
diff --git a/gbpservice/neutron/services/grouppolicy/group_policy_driver_api.py b/gbpservice/neutron/services/grouppolicy/group_policy_driver_api.py
index ee4574737..e33f037bd 100644
--- a/gbpservice/neutron/services/grouppolicy/group_policy_driver_api.py
+++ b/gbpservice/neutron/services/grouppolicy/group_policy_driver_api.py
@@ -22,6 +22,7 @@ VALIDATION_PASSED = "passed"
 VALIDATION_REPAIRED = "repaired"
 VALIDATION_FAILED_REPAIRABLE = "failed repairable"
 VALIDATION_FAILED_UNREPAIRABLE = "failed unrepairable"
+VALIDATION_FAILED_BINDING_PORTS = "failed binding ports"
 
 
 @six.add_metaclass(abc.ABCMeta)
diff --git a/gbpservice/neutron/tests/unit/services/grouppolicy/test_aim_validation.py b/gbpservice/neutron/tests/unit/services/grouppolicy/test_aim_validation.py
index 32d03f92b..9c7126cd1 100644
--- a/gbpservice/neutron/tests/unit/services/grouppolicy/test_aim_validation.py
+++ b/gbpservice/neutron/tests/unit/services/grouppolicy/test_aim_validation.py
@@ -64,6 +64,12 @@ class AimValidationTestMixin(object):
             api.VALIDATION_FAILED_UNREPAIRABLE,
             self.av_mgr.validate(repair=True))
 
+    def _validate_fails_binding_ports(self):
+        # Repair should fail.
+        self.assertEqual(
+            api.VALIDATION_FAILED_BINDING_PORTS,
+            self.av_mgr.validate(repair=True))
+
     def _test_aim_resource(self, resource, unexpected_attr_name='name',
                            unexpected_attr_value='unexpected',
                            test_unexpected_monitored=True):
@@ -862,7 +868,7 @@ class TestNeutronMapping(AimValidationTestCase):
                                                  'host': 'yyy'})
         self.db_session.query(ml2_models.PortBinding).filter_by(
             port_id=port['id']).update({'host': 'yyy'})
-        self._validate_unrepairable()
+        self._validate_fails_binding_ports()
 
     def test_legacy_cleanup(self):
         # Create external network.