Update how-to-connect-to-data-source-privately.md

Author: braieralves

articles/managed-grafana/how-to-connect-to-data-source-privately.md

@@ -34,7 +34,7 @@ Managed private endpoints work with Azure services that support private link. Us
 - Azure SQL server
 - Private link services
 - Azure Databricks
-- Azure Database for PostgreSQL flexible servers
+- Azure Database for PostgreSQL flexible servers ([Only for servers that have public access networking](https://learn.microsoft.com/en-us/azure/postgresql/flexible-server/concepts-networking-private-link))
 
 ## Prerequisites