fixed the entra ref back

Author: george-guirguis

articles/event-grid/mqtt-overview.md

@@ -75,7 +75,7 @@ IoT applications are software designed to interact with and process data from Io
 
 ### Client authentication
 
-Event Grid has a client registry that stores information about the clients permitted to connect to it. Before a client can connect, there must be an entry for that client in the client registry. As a client connects to MQTT broker, it needs to authenticate with MQTT broker based on credentials stored in the identity registry. MQTT broker supports X.509 certificate authentication that is the industry authentication standard in IoT devices and [Microsoft Entra ID (formerly Azure Active Directory)](mqtt-client-azure-ad-token-and-rbac.md) that is Azure's authentication standard for applications.[Learn more about MQTT client authentication.](mqtt-client-authentication.md) 
+Event Grid has a client registry that stores information about the clients permitted to connect to it. Before a client can connect, there must be an entry for that client in the client registry. As a client connects to MQTT broker, it needs to authenticate with MQTT broker based on credentials stored in the identity registry. MQTT broker supports X.509 certificate authentication that is the industry authentication standard in IoT devices and [Microsoft Entra ID](mqtt-client-microsoft-entra-token-and-rbac.md) that is Azure's authentication standard for applications.[Learn more about MQTT client authentication.](mqtt-client-authentication.md)
 
 ### Access control