CrmSoapExtension detected CrmException:
System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> Microsoft.Crm.CrmArgumentException: Condition for attribute 'email.subject': expected argument(s) of type 'System.String' but received 'System.DBNull'. ---> System.ArgumentException: Condition for attribute 'email.subject': expected argument(s) of type 'System.String' but received 'System.DBNull'.
--- End of inner exception stack trace ---
at Microsoft.Crm.Query.ConditionExpression..ctor(AttributeMetadata attribute, ConditionOperator conditionOperator, Array values, Boolean isCustom)
at Microsoft.Crm.BusinessEntities.PagingHelper.AddFiltering(OrderExpressionCollection orderCollection, FilterExpression filterExpression, Hashtable orderNameValuePairs, Boolean pageBack)
at Microsoft.Crm.BusinessEntities.PagingHelper.AddPagingFilters(EntityExpression entityExpression)
at Microsoft.Crm.BusinessEntities.BusinessProcessObject.DoRetrieveMultiple(BusinessEntityCollection entities, EntityExpression entityExp, ExecutionContext context)
at Microsoft.Crm.BusinessEntities.BusinessProcessObject.RetrieveMultiple(EntityExpression entityExpression, ExecutionContext context)
at Microsoft.Crm.ObjectModel.CommunicationActivityServiceBase.RetrieveMultiple(EntityExpression entityExpression, ExecutionContext context)
at Microsoft.Crm.BusinessEntities.BusinessProcessObject.RetrieveMultiple(EntityExpression entityExpression)
at Microsoft.Crm.ObjectModel.QueryService.RetrieveMultiple(EntityExpression entityExpression)
at Microsoft.Crm.WebServices.QueryWebService.RetrieveMultiple(QueryBase query)
--- End of inner exception stack trace ---
====================================
User Error
Invalid Argument
Error Code: 0x80040203