diff --git a/prometheus-entrouvert-exporter/prometheus-system-exporter.py b/prometheus-entrouvert-exporter/prometheus-system-exporter.py
index e2abeb1..c7bf581 100755
--- a/prometheus-entrouvert-exporter/prometheus-system-exporter.py
+++ b/prometheus-entrouvert-exporter/prometheus-system-exporter.py
@@ -236,7 +236,7 @@ def units(ctn):
     if name:
         eo_units.labels(ctn, name, "failed").set(n)
     else:
-        eo_units.labels(ctn, "failed").set(n)
+        eo_units.labels(ctn, "", "failed").set(n)
 
 
 def run_in_machines(ctn):