diff --git a/app/Jobs/SyncSubscriberToMailwizz.php b/app/Jobs/SyncSubscriberToMailwizz.php
index 2c474d0..c414f02 100644
--- a/app/Jobs/SyncSubscriberToMailwizz.php
+++ b/app/Jobs/SyncSubscriberToMailwizz.php
@@ -14,7 +14,6 @@ use Illuminate\Contracts\Queue\ShouldBeUnique;
 use Illuminate\Contracts\Queue\ShouldQueueAfterCommit;
 use Illuminate\Foundation\Bus\Dispatchable;
 use Illuminate\Queue\InteractsWithQueue;
-use Illuminate\Queue\SerializesModels;
 use Illuminate\Support\Facades\Log;
 use RuntimeException;
 use Throwable;
@@ -24,7 +23,6 @@ class SyncSubscriberToMailwizz implements ShouldBeUnique, ShouldQueueAfterCommit
     use Dispatchable;
     use InteractsWithQueue;
     use Queueable;
-    use SerializesModels;
 
     /**
      * Seconds before the unique lock expires if the worker dies before releasing it.
@@ -38,23 +36,42 @@ class SyncSubscriberToMailwizz implements ShouldBeUnique, ShouldQueueAfterCommit
      */
     public array $backoff = [10, 30, 60];
 
-    public function __construct(public Subscriber $subscriber)
+    /**
+     * Set in the constructor for new jobs. Remains null when an old queue payload (pre–subscriber-id refactor) is unserialized.
+     */
+    public ?int $subscriberId = null;
+
+    /**
+     * @param  Subscriber|int  $subscriber  Model is accepted when dispatching; only the id is serialized for the queue.
+     */
+    public function __construct(Subscriber|int $subscriber)
     {
+        $this->subscriberId = $subscriber instanceof Subscriber
+            ? (int) $subscriber->getKey()
+            : $subscriber;
         $this->onQueue('mailwizz');
     }
 
     public function uniqueId(): string
     {
-        return (string) $this->subscriber->getKey();
+        return $this->subscriberId !== null
+            ? (string) $this->subscriberId
+            : 'stale-mailwizz-sync-payload';
     }
 
     public function handle(): void
     {
+        if ($this->subscriberId === null) {
+            Log::notice('SyncSubscriberToMailwizz: skipped job with missing subscriber id (stale queue payload). Clear the queue or re-dispatch sync jobs.');
+
+            return;
+        }
+
         try {
             $this->runSync();
         } catch (Throwable $e) {
             Log::error('SyncSubscriberToMailwizz: integration failed; subscriber remains local (use admin resync if needed)', [
-                'subscriber_id' => $this->subscriber->id,
+                'subscriber_id' => $this->subscriberId,
                 'message' => $e->getMessage(),
             ]);
         }
@@ -64,7 +81,7 @@ class SyncSubscriberToMailwizz implements ShouldBeUnique, ShouldQueueAfterCommit
     {
         $subscriber = Subscriber::query()
             ->with(['preregistrationPage.mailwizzConfig'])
-            ->find($this->subscriber->id);
+            ->find($this->subscriberId);
 
         if ($subscriber === null) {
             return;
@@ -115,7 +132,7 @@ class SyncSubscriberToMailwizz implements ShouldBeUnique, ShouldQueueAfterCommit
     public function failed(?Throwable $exception): void
     {
         Log::error('SyncSubscriberToMailwizz failed', [
-            'subscriber_id' => $this->subscriber->id,
+            'subscriber_id' => $this->subscriberId,
             'message' => $exception?->getMessage(),
         ]);
     }