diff --git a/backend/login.php b/backend/login.php
index 8638476..0b37970 100644
--- a/backend/login.php
+++ b/backend/login.php
@@ -12,6 +12,10 @@ $success = '';
 // Detect the correct callback URL
 $scheme = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') ? 'https' : 'http';
 $host = $_SERVER['HTTP_HOST'] ?? 'localhost:8080';
+// If no port in host and not standard port, add it
+if (strpos($host, ':') === false && !in_array($_SERVER['SERVER_PORT'] ?? 80, [80, 443])) {
+    $host .= ':' . $_SERVER['SERVER_PORT'];
+}
 $callbackUrl = "$scheme://$host/login.php";
 
 if (isset($_GET['auth'])) {