diff --git a/flask_cas/routing.py b/flask_cas/routing.py
index 6078b79c..dc2ee5d6 100644
--- a/flask_cas/routing.py
+++ b/flask_cas/routing.py
@@ -87,8 +87,8 @@ def logout():
     flask.session.pop(cas_token_session_key, None)  # added by EV
     flask.session.pop("CAS_EDT_ID", None)  # added by EV
 
-    cas_after_logout = current_app.config["CAS_AFTER_LOGOUT"]
-    if cas_after_logout is not None:
+    cas_after_logout = current_app.config.get("CAS_AFTER_LOGOUT")
+    if cas_after_logout:
         # If config starts with http, use it as dest URL.
         # Else, build Flask URL
         dest_url = (