Report Not opening in report manager

Hi SSRS GURUS

I have created a report and deployed it to the reporting server. I went to the reporting manager and i can see the report under my reports folder. The strange thing is i can see the report when i click  and select the "Edit in the Report Builder" , but when i click on the report to view it i'm getting the below message, any ideas where am messing the report???/

• Cannot create a connection to data source 'DataSource1'. (rsErrorOpeningConnection)
  • The connection either timed out or was lost.
    • Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
      • An existing connection was forcibly closed by the remote host