diff --git a/flask_simpleldap/__init__.py b/flask_simpleldap/__init__.py
index 612a223..ba5afd9 100644
--- a/flask_simpleldap/__init__.py
+++ b/flask_simpleldap/__init__.py
@@ -431,7 +431,7 @@ def basic_auth_required(self, func):
 
         def make_auth_required_response():
             response = make_response("Unauthorized", 401)
-            response.www_authenticate.set_basic(current_app.config["LDAP_REALM_NAME"])
+            response.headers['WWW-Authenticate'] = f'Basic realm="{current_app.config["LDAP_REALM_NAME"]}"'
             return response
 
         @wraps(func)