diff --git a/en/docs/api-security/runtime/api-authentication/secure-apis-using-basic-authentication.md b/en/docs/api-security/runtime/api-authentication/secure-apis-using-basic-authentication.md
index 2ac32e83cb..4cc152ed9f 100644
--- a/en/docs/api-security/runtime/api-authentication/secure-apis-using-basic-authentication.md
+++ b/en/docs/api-security/runtime/api-authentication/secure-apis-using-basic-authentication.md
@@ -6,6 +6,9 @@ the OAuth2 and Basic schemes at the same time.
 
 The subsequent sections explain how you can work with Basic Authentication on the WSO2 API Gateway.
 
+!!! note
+    Basic Authentication is only supported with the **WSO2 resident Key Manager**. When a third-party Key Manager is configured, use OAuth2-based authentication instead.
+
 ## Enabling Basic Authentication for an API
 Basic Authentication is an API level configuration. Please sign in to the API Publisher and click on the API that you need to configure the 
 Basic Authentication. Under the Application Level Security section in the Runtime Configuration of the API Details page allow users to configure