diff --git a/authens/views.py b/authens/views.py
index fc63867..bcdc702 100644
--- a/authens/views.py
+++ b/authens/views.py
@@ -32,7 +32,7 @@ class NextPageMixin:
             del request.session["CASNEXT"]
         if next_url is None:
             next_url = settings.LOGIN_REDIRECT_URL
-        return next_url
+        return str(next_url)
 
 
 class LoginSwitchView(NextPageMixin, TemplateView):