diff --git a/system/postmaster/services/Mailchimp.php b/system/postmaster/services/Mailchimp.php
old mode 100644
new mode 100755
index 00f73aa..f2a026c
--- a/system/postmaster/services/Mailchimp.php
+++ b/system/postmaster/services/Mailchimp.php
@@ -388,7 +388,7 @@ public function subscribe($data)
 		{
 			$i = count($groupings);
 
-			$groupings[$i] = array('groups' => $data['post']['groups']);
+			$groupings[$i] = array('groups' => implode(",", $data['post']['groups']));
 
 			if(isset($data['post']['group_id']))
 			{