diff --git a/extensions/lock/extend.php b/extensions/lock/extend.php
index 0e7b55cd5..beff8eae8 100644
--- a/extensions/lock/extend.php
+++ b/extensions/lock/extend.php
@@ -47,14 +47,16 @@ return [
         ->type(DiscussionLockedPost::class),
 
     (new Extend\Event())
-        ->listen(ConfigureDiscussionGambits::class, function (ConfigureDiscussionGambits $event) {
-            $event->gambits->add(LockedGambit::class);
-        })
         ->listen(Saving::class, Listener\SaveLockedToDatabase::class)
         ->listen(DiscussionWasLocked::class, Listener\CreatePostWhenDiscussionIsLocked::class)
         ->listen(DiscussionWasUnlocked::class, Listener\CreatePostWhenDiscussionIsUnlocked::class),
 
+    (new Extend\Policy())
+        ->modelPolicy(Discussion::class, Access\DiscussionPolicy::class),
+
     function (Dispatcher $events) {
-        $events->subscribe(Access\DiscussionPolicy::class);
+        $events->listen(ConfigureDiscussionGambits::class, function (ConfigureDiscussionGambits $event) {
+            $event->gambits->add(LockedGambit::class);
+        });
     },
 ];
diff --git a/extensions/lock/src/Access/DiscussionPolicy.php b/extensions/lock/src/Access/DiscussionPolicy.php
index a8cb4ca75..643136a15 100755
--- a/extensions/lock/src/Access/DiscussionPolicy.php
+++ b/extensions/lock/src/Access/DiscussionPolicy.php
@@ -10,16 +10,11 @@
 namespace Flarum\Lock\Access;
 
 use Flarum\Discussion\Discussion;
-use Flarum\User\AbstractPolicy;
+use Flarum\User\Access\AbstractPolicy;
 use Flarum\User\User;
 
 class DiscussionPolicy extends AbstractPolicy
 {
-    /**
-     * {@inheritdoc}
-     */
-    protected $model = Discussion::class;
-
     /**
      * @param User $actor
      * @param Discussion $discussion
@@ -28,7 +23,7 @@ class DiscussionPolicy extends AbstractPolicy
     public function reply(User $actor, Discussion $discussion)
     {
         if ($discussion->is_locked && $actor->cannot('lock', $discussion)) {
-            return false;
+            return $this->deny();
         }
     }
 }