Error for some users while exporting to FIM CS

Getting below error for some users while exporting to FIM CS, all the users were successfully exported before without any issue, I can see all the users are there in FIM.

Please help

Fault Reason: The request message contains errors that prevent processing the request.\r\n\r\nFault Details: <RepresentationFailures xmlns="http://schemas.microsoft.com/2006/11/ResourceManagement" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><AttributeRepresentationFailure><AttributeType>AccountName</AttributeType><AttributeValue></AttributeValue><FailureMessage>Exception: ValueViolatesUniqueness Target(s): VenkataRama Bolla
Stack Trace: Microsoft.ResourceManagement.WebServices.Exceptions.InvalidRepresentationException: ValueViolatesUniqueness
   at Microsoft.ResourceManagement.Utilities.ExceptionManager.ThrowException(Exception exception)
   at Microsoft.ResourceManagement.Data.Exception.DataAccessExceptionManager.ThrowException(SqlException innerException, TransactionAndConnectionScope scope)
   at Microsoft.ResourceManagement.Data.DataAccess.ProcessRequest(RequestType request)
   at Microsoft.ResourceManagement.ActionProcessor.ActionDispatcher.ProcessInputRequest(RequestType request)
   at Microsoft.ResourceManagement.WebServices.RequestDispatcher.ExecuteAction(RequestType request)
   at Microsoft.ResourceManagement.WebServices.RequestDispatcher.ExecuteAction[ResponseBodyType](RequestType request)
   at Microsoft.ResourceManagement.WebServices.RequestDispatcher.DispatchRequest[ResponseBodyType](RequestType request, Guid requestIdentifier, Object redispatchSingleInstanceKey, Boolean isRedispatch)
   at Microsoft.ResourceManagement.WebServices.RequestDispatcher.DispatchRequest[ResponseBodyType](RequestType request)
   at Microsoft.ResourceManagement.WebServices.ResourceManagementService.Create(Message request)</FailureMessage><AttributeFailureCode>ValueViolatesUniqueness</AttributeFailureCode><AdditionalTextDetails>The specified attribute value must be unique for this Resource Type.</AdditionalTextDetails></AttributeRepresentationFailure><CorrelationId>a692fddf-b075-499a-bc13-df34d58c69ab</CorrelationId></RepresentationFailures>

Thanks & Regards,

Sudhish