diff --git a/config/horizon.php b/config/horizon.php
index 0bf87fba..1e05c1b8 100644
--- a/config/horizon.php
+++ b/config/horizon.php
@@ -15,7 +15,7 @@
     |
     */
 
-    'domain' => env('HORIZON_DOMAIN', null),
+    'domain' => env('HORIZON_DOMAIN'),
 
     /*
     |--------------------------------------------------------------------------