diff --git a/global/overlay/etc/puppet/modules/cdn/manifests/mqtt.pp b/global/overlay/etc/puppet/modules/cdn/manifests/mqtt.pp
index f70b4b7..6da7643 100644
--- a/global/overlay/etc/puppet/modules/cdn/manifests/mqtt.pp
+++ b/global/overlay/etc/puppet/modules/cdn/manifests/mqtt.pp
@@ -1,7 +1,7 @@
 # Configure a SUNET CDN mqtt server
 class cdn::mqtt(
   String $dc = '',
-  Array[String] clients = [],
+  Array[String] $clients = [],
   Hash[String, Hash] $bridges = {},
 )
 {