Help Getting Security error while connecting to Exchange Server

[ronanki.2002]

Hi

I have a Samsung Galaxy S2. I want to configure my Exchange mails in my Mobile. I have successfully created my account details and connected to the Exchange Server.I am able to view the Mobile device details in Exchange Server but it not in Sync state or it is not showing the last sync state. In the Mobile I am getting the error as "Getting Security Error while connecting to the Server"

Thanks
Sudhakar