diff --git a/app.js b/app.js
index e5bf257..e1eb475 100644
--- a/app.js
+++ b/app.js
@@ -992,6 +992,10 @@ function updatePortInUrl(url) {
     console.error('Invalid URL format:', url);
     return '';
   }
+  if (url === '') {
+    console.error('Empty URL:', url);
+    return '';
+  }
   const urlObj = new URL(url);
   urlObj.port = servePort;
   return urlObj.toString();