added limitation

add section on limitation with custom ssl policy across different listeners with same port

Author: mscatyao

articles/application-gateway/application-gateway-configure-listener-specific-ssl-policy.md

@@ -72,6 +72,9 @@ Now that we've created an SSL profile with a listener-specific SSL policy, we ne
 
     ![Associate SSL profile to new listener](./media/mutual-authentication-portal/mutual-authentication-listener-portal.png)        
 
+### Limitations
+There is a limitation right now on Application Gateway where different listeners using the same port cannot have the same custom SSL policy configured. To ensure that the custom protocols configured as part of the custom SSL policy are applied to a listener, make sure that different listeners are running on different ports or configure the same custom SSL policy with the same custom protocols across all listeners running on the same port. 
+
 ## Next steps
 
 > [!div class="nextstepaction"]