masstransit with rabbitmq: Why message auto moved to ***_skipped queue when it responing

[danny...@hotmail.com]

UCITY.API  Request To UCITY.USER 

Trace Log：

2018-03-23 15:59:22.5727|DEBUG|MassTransit.Messages|SEND rabbitmq://192.168.1.142/us/ucity_us_mobilephonecomplete 0b350000-dafb-1866-5b48-08d59093fd36 MQNamespace.USER.IMobilephoneCompleteRequest

2018-03-23 15:59:22.6077|DEBUG|MassTransit.Messages|SKIP rabbitmq://192.168.1.142/us/bus-WIN-VH8418VRIC5-UCITY.API-bc4oyyg49ccgcqg6bdk3br7trf?durable=false&autodelete=true N/A

he server reported 1 messages remaining.

Exchange	bus-WIN-VH8418VRIC5-UCITY.API-bc4oyyg49ccgcqg6bdk3br7trf_skipped
Routing Key
Redelivered	●
Properties	message_id: 0b350000-dafb-1866-d0af-08d59093bae2 delivery_mode: 2 headers: Content-Type: application/vnd.masstransit+json publishId: 1 MT-Reason: dead-letter MT-Host-MachineName: WIN-VH8418VRIC5 MT-Host-ProcessName: UCITY.API MT-Host-ProcessId: 14648 MT-Host-Assembly: UCITY.API MT-Host-AssemblyVersion: 1.0.0.0 MT-Host-MassTransitVersion: 4.0.1.1390 MT-Host-FrameworkVersion: 4.0.30319.42000 MT-Host-OperatingSystemVersion: Microsoft Windows NT 6.2.9200.0 content_type: application/vnd.masstransit+json
Payload1060 bytesEncoding: string	{ "messageId": "0b350000-dafb-1866-d0af-08d59093bae2", "requestId": "0b350000-dafb-1866-8267-08d59093bade", "conversationId": "0b350000-dafb-1866-0ddf-08d59093bae2", "sourceAddress": "rabbitmq://192.168.1.142/us/ucity_us_mobilephonecomplete", "destinationAddress": "rabbitmq://192.168.1.142/us/bus-WIN-VH8418VRIC5-UCITY.API-bc4oyyg49ccgcqg6bdk3br7trf?durable=false&autodelete=true", "messageType": [ "urn:message:MQNamespace:IBaseResponseModel" ], "message": { "code": 4212, "correlationId": "73989f86-51fd-4ae1-a467-a556a165f125", "message": "COMPLETEMOBILEPHONE FAILD!USERWECHAT MOBILEPHONE COMPLETED", "timeStamp": "2018-03-23T15:57:31.3218406+08:00" }, "headers": {}, "host": { "machineName": "WIN-VH8418VRIC5", "processName": "UCITY.USER", "processId": 8952, "assembly": "UCITY.USER", "assemblyVersion": "1.0.0.0", "frameworkVersion": "4.0.30319.42000", "massTransitVersion": "4.0.1.1390", "operatingSystemVersion": "Microsoft Windows NT 6.2.9200.0" } }