diff --git a/ext/flexmailer/src/API/MailingPreview.php b/ext/flexmailer/src/API/MailingPreview.php
index cdd11ac4281a..e585eda77ab7 100644
--- a/ext/flexmailer/src/API/MailingPreview.php
+++ b/ext/flexmailer/src/API/MailingPreview.php
@@ -41,11 +41,23 @@ public static function preview($apiRequest) {
     $contactID = \CRM_Utils_Array::value('contact_id', $params,
       \CRM_Core_Session::singleton()->get('userID'));
 
-    $job = new \CRM_Mailing_BAO_MailingJob();
+    $job = new class extends \CRM_Mailing_BAO_MailingJob {
+
+      public function insert() {
+        throw new \RuntimeException('MailingJob is just a preview. It cannot be saved.');
+      }
+
+      public function update($dataObject = FALSE) {
+        throw new \RuntimeException('MailingJob is just a preview. It cannot be saved.');
+      }
+
+      public function save($hook = TRUE) {
+        throw new \RuntimeException('MailingJob is just a preview. It cannot be saved.');
+      }
+
+    };
     $job->mailing_id = $mailing->id ?: NULL;
-    $job->is_test = 1;
     $job->status = 'Complete';
-    // $job->save();
 
     $flexMailer = new FlexMailer(array(
       'is_preview' => TRUE,
diff --git a/ext/flexmailer/tests/phpunit/Civi/FlexMailer/MailingPreviewTest.php b/ext/flexmailer/tests/phpunit/Civi/FlexMailer/MailingPreviewTest.php
index aad8443ce470..a12ddad7c576 100644
--- a/ext/flexmailer/tests/phpunit/Civi/FlexMailer/MailingPreviewTest.php
+++ b/ext/flexmailer/tests/phpunit/Civi/FlexMailer/MailingPreviewTest.php
@@ -83,7 +83,7 @@ public function testMailerPreview(): void {
     $this->assertMaxIds($maxIDs);
 
     $previewResult = $result['values'][$result['id']]['api.Mailing.preview'];
-    $this->assertEquals("[CiviMail Draft] Hello $displayName",
+    $this->assertEquals("Hello $displayName",
       $previewResult['values']['subject']);
 
     $this->assertStringContainsString("This is $displayName", $previewResult['values']['body_text']);
@@ -112,7 +112,7 @@ public function testMailerPreviewWithoutId(): void {
     $previewResult = $this->callAPISuccess('mailing', 'preview', $params);
     $this->assertMaxIds($maxIDs);
 
-    $this->assertEquals("[CiviMail Draft] Hello $displayName",
+    $this->assertEquals("Hello $displayName",
       $previewResult['values']['subject']);
 
     $this->assertStringContainsString("This is $displayName", $previewResult['values']['body_text']);