Configuration Manager was unable to connect to the RPC server. Ensure the source site is on-line and accessible and that ...

Configuration Manager was unable to connect to the RPC server. Ensure the source site is on-line and accessible and that firewall exceptions are configured and include the following ports: 445 (TCP), 135 (TCP). If this error occurs while gathering data from the top-level site server for a new source hierarchy, ensure the correct NetBIOS name or FQDN is specified.