diff --git a/app/services/notification_service.rb b/app/services/notification_service.rb
index 06140c5..3547552 100644
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
@@ -254,7 +254,7 @@ class NotificationService
   # Remove users with disabled notifications from array
   # Also remove duplications and nil recipients
   def reject_muted_users(users, project = nil)
-    users = users.compact.uniq
+    users = users.to_a.compact.uniq
 
     users.reject do |user|
       next user.notification.disabled? unless project
--
libgit2 0.21.2