diff --git a/src/AuthTwoFactorPage.php b/src/AuthTwoFactorPage.php
index 94bd70b..d8a5d62 100644
--- a/src/AuthTwoFactorPage.php
+++ b/src/AuthTwoFactorPage.php
@@ -26,7 +26,8 @@ final class AuthTwoFactorPage {
         // Store token in session so the poll endpoint can reference it
         $_SESSION['pending_2fa_approval_token'] = $rawToken;
 
-        $approveUrl = 'https://apps.f0xx.org' . $project . '/two-factor/approve?token=' . urlencode($rawToken);
+        $origin = rtrim((string) cfg('public_origin', 'https://apps.f0xx.org'), '/');
+        $approveUrl = $origin . $project . '/two-factor/approve?token=' . urlencode($rawToken);
 
         $payload = [
             'long_url'  => $approveUrl,