• in the RS log files the error is

    library!WindowsService_0!560!06/19/2014-06:00:08:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.InvalidDataSourceCredentialSettingException: , Microsoft.ReportingServices.Diagnostics.Utilities.InvalidDataSourceCredentialSettingException: The current action cannot be completed. The user data source credentials do not meet the requirements to run this report or shared dataset. Either the user data source credentials are not stored in the report server database, or the user data source is configured not to require credentials but the unattended execution account is not specified.;

    library!WindowsService_0!560!06/19/2014-06:00:08:: w WARN: Microsoft.ReportingServices.Diagnostics.Utilities.InvalidDataSourceCredentialSettingException: The current action cannot be completed. The user data source credentials do not meet the requirements to run this report or shared dataset. Either the user data source credentials are not stored in the report server database, or the user data source is configured not to require credentials but the unattended execution account is not specified.

    library!WindowsService_0!560!06/19/2014-06:00:08:: i INFO: Initializing EnableExecutionLogging to 'True' as specified in Server system properties.

    emailextension!WindowsService_0!560!06/19/2014-06:00:08:: e ERROR: Error sending email. Microsoft.ReportingServices.Diagnostics.Utilities.RSException: The current action cannot be completed. The user data source credentials do not meet the requirements to run this report or shared dataset. Either the user data source credentials are not stored in the report server database, or the user data source is configured not to require credentials but the unattended execution account is not specified. ---> Microsoft.ReportingServices.Diagnostics.Utilities.InvalidDataSourceCredentialSettingException: The current action cannot be completed. The user data source credentials do not meet the requirements to run this report or shared dataset. Either the user data source credentials are not stored in the report server database, or the user data source is configured not to require credentials but the unattended execution account is not specified.

    notification!WindowsService_0!560!06/19/2014-06:00:08:: e ERROR: Error occured processing subscription 3a163404-d78c-486c-bd7c-a124a6f0bdbe: Failure sending mail: The current action cannot be completed. The user data source credentials do not meet the requirements to run this report or shared dataset. Either the user data source credentials are not stored in the report server database, or the user data source is configured not to require credentials but the unattended execution account is not specified.Mail will not be resent.

    The data source is IBM and it's shared and unnatend account is a domain user.