diff --git a/src/Notifications/AlertRaised.php b/src/Notifications/AlertRaised.php
index cc805ca..72f50a7 100644
--- a/src/Notifications/AlertRaised.php
+++ b/src/Notifications/AlertRaised.php
@@ -14,7 +14,7 @@ public function toArray(): array
         return array_merge(
             parent::toArray(),
             [
-                'locations' => implode(',', Arr::get($this->alert, 'locations')),
+                'locations' => implode(',', Arr::get($this->alert, 'locations', [])),
             ]
         );
     }