diff --git a/monasca_agent/common/aggregator.py b/monasca_agent/common/aggregator.py
index 9ed9d8a2..afe37380 100644
--- a/monasca_agent/common/aggregator.py
+++ b/monasca_agent/common/aggregator.py
@@ -54,7 +54,7 @@ class MetricsAggregator(object):
             try:
                 metrics.extend(metric.flush())
             except Exception:
-                log.exception('Error flushing {0} metrics.'.format(metric.name))
+                log.exception('Error flushing {0} metrics.'.format(metric.metric['name']))
 
         # Log a warning regarding metrics with old timestamps being submitted
         if self.num_discarded_old_points > 0:
diff --git a/monasca_agent/common/metrics.py b/monasca_agent/common/metrics.py
index f25d9e20..3f30768e 100644
--- a/monasca_agent/common/metrics.py
+++ b/monasca_agent/common/metrics.py
@@ -53,6 +53,13 @@ class Metric(object):
     def flush(self):
         if self.timestamp is None:
             return []
+        if self.value is None:
+            log.error('Value of None is not supported, will not send. '
+                      'Metric %s with dimensions %s at time %d',
+                      self.metric['name'],
+                      self.metric['dimensions'],
+                      self.timestamp)
+            return []
 
         envelope = self.measurement(self.value, self.timestamp)
         self.timestamp = None