调用客户WEB API报错

调用客户查询接口
Kingdee.BOS.WebApi.ServicesStub.DynamicFormService.View.common.kdsvc
其中SessionKey
aspnetsessionkey
都是从登陆接口返回的Header中取出，json入参如下

{"formid":"BD_Customer","obj":{"CreateOrgId":0,"Number":"CUST0001","Id":"CUST0001"}}
返回如：
{"Result":{"ResponseStatus":{"ErrorCode":500,"IsSuccess":false,"Errors":[{"FieldName":"Object reference not set to an instance of an object.","Message":" at Kingdee.BOS.WebApi.FormService.View.Execute()\r\n at Kingdee.BOS.WebApi.FormService.BillOperationService.ExecuteOperation(FormOperation op, String data)","DIndex":0}],"SuccessEntitys":[]}}}

不知道返回是什么样的错