Hi All,I receive error messages on my client acess(with hub transport server) and mail server. Below is the error message on my mail server. My client acess server also receive this error message. Anyone know how to solve this issue.Thank you.--------------------------------------------------------Microsoft Exchange Error--------------------------------------------------------The following error(s) were reported while loading topology information: Get-ActiveSyncVirtualDirectoryFailedError:The task was not able to connect to IIS on the server 'abcowa.abc.org'. Ensure that the server exists and is reachable from this computer: The RPC server is unavailable. Get-OabVirtualDirectoryFailedError:The task was not able to connect to IIS on the server'abcowa.abc.org'. Ensure that the server exists and is reachable from this computer: The RPC server is unavailable. Get-OWAVirtualDirectoryFailedError:The task was not able to connect to IIS on the server'abcowa.abc.org'. Ensure that the server exists and is reachable from this computer: The RPC server is unavailable. --------------------------------------------------------OK--------------------------------------------------------Doreen

Hi Dorren, Could you please describe your environment in detail? How many CAS server do you have? Whats the OS? Is there an ISA server? Is there any related event log? Please disable the firewall and test the issue. Here is a similar issue which was fixed by reconfiguring Windows firewall. http://social.technet.microsoft.com/Forums/en-US/exchangesvrdeploy/thread/9ac477b5-620e-4fd5-8499-42ede3611af8/ Please make sure port 135 is working. Meanwhile, I suggest you download ExBPA to have a health check for the Exchange Server. Thanks, Elvis

Hi Doreen,Is there any update on the issue? If any problems, please let me know. Thank you,Elvis