SSRS Cannot create a connection to data source “*****（rsErrorOpenningConnection）”

An error has occurred during report processing. (rsProcessingAborted)
Cannot create a connection to data source 'dsFederatedSample_SurveyLevel_STG'. (rsErrorOpeningConnection)
For more information about this error navigate to the report server on the local server machine, or enable remote errors

处办法如下：在管理页面中，取消Log in using these credentials,but ehn try to impersonate the user viewing the report.