Fix empty serverURL did not redirect properly

Signed-off-by: toshi0123 <7948737+toshi0123@users.noreply.github.com>

lib/response.js

@@ -23,7 +23,7 @@ var response = {
       responseError(res, '403', 'Forbidden', 'oh no.')
     } else {
       req.flash('error', 'You are not allowed to access this page. Maybe try logging in?')
-      res.redirect(config.serverURL)
+      res.redirect(config.serverURL + '/')
     }
   },
   errorNotFound: function (res) {