diff --git a/app.py b/app.py
index c2ce731..0b7e051 100644
--- a/app.py
+++ b/app.py
@@ -560,7 +560,7 @@ def _update_npm_config(credentials=None):
         credentials = session.get("auth_credentials")
     # If credentials are provided, we skip the session check as the user has already been authenticated
     
-    npm = NginxProxyManager(app_config.NPM_HOST, app_config.NPM_EMAIL, app_config.NPM_PASSWORD)
+    npm = NginxProxyManager(app.config['NPM_HOST'], app.config['NPM_EMAIL'], app.config['NPM_PASSWORD'])
     npm.login()
     host = npm.get_proxy_host(9)
     if host: