diff --git a/roles/unbound/files/prometheus-unbound-exporter.service b/roles/unbound/files/prometheus-unbound-exporter.service
index d3b4c9f..523badd 100644
--- a/roles/unbound/files/prometheus-unbound-exporter.service
+++ b/roles/unbound/files/prometheus-unbound-exporter.service
@@ -6,7 +6,7 @@ After=network.target
 [Service]
 Type=simple
 EnvironmentFile=/etc/prometheus-unbound-exporter.conf
-ExecStart=/bin/unbound_exporter ${UNBOUND_EXPORTER_ARGS}
+ExecStart=/bin/unbound_exporter $UNBOUND_EXPORTER_ARGS
 
 [Install]
 WantedBy=multi-user.target