diff --git a/lib/classes/ssl/class.lescript.php b/lib/classes/ssl/class.lescript.php
index ab4a30a3..305a3502 100644
--- a/lib/classes/ssl/class.lescript.php
+++ b/lib/classes/ssl/class.lescript.php
@@ -100,9 +100,13 @@ class lescript
                 array("resource" => "new-authz", "identifier" => array("type" => "dns", "value" => $domain))
             );
 
+            if (!array_key_exists('challenges', $response)) {
+	        throw new RuntimeException("No challenges received for $domain. Whole response: ".json_encode($response));
+            }
+
             // choose http-01 challange only
             $challenge = array_reduce($response['challenges'], function($v, $w) { return $v ? $v : ($w['type'] == 'http-01' ? $w : false); });
-            if(!$challenge) throw new \RuntimeException("HTTP Challenge for $domain is not available. Whole response: ".json_encode($response));
+            if(!$challenge) throw new RuntimeException("HTTP Challenge for $domain is not available. Whole response: ".json_encode($response));
 
             $this->log("Got challenge token for $domain");
             $location = $this->client->getLastLocation();