I am getting the following error ( which it was working fine previously )

**An error has occurred during report processing. (rsProcessingAborted)
The execution failed for the shared data set 'CombinedStatsPerClient'. (rsDataSetExecutionError)
Cannot create a connection to data source ' Data source for shared dataset'. (rsErrorOpeningConnection)
For more information about this error navigate to the report server on the local server machine, or enable remote errors**

What can be the issue, Connection..or