[嗨，我有一个带有自定义序列（dblookup和切换序列）的API，它将验证用户是否存在于数据库中，如果不存在，它应该发送http状态401：未经授权，以下是案例代码，但我总是得到错误无法推断运输信息。发送回响应消息的正确方法是什么。
谢谢，提请
<case regex="0">
<log level="custom">
<property name="ucount" expression="fn:concat('User login - ', get-property('employee_count'))"/>
</log>
<send>
<property name="RESPONSE" value="true" scope="default"/>
<property name="NO_ENTITY_BODY" action="remove" scope="axis2"/>
<property name="HTTP_SC" value="401" scope="axis2"/>
<header name="To" action="remove"/>
<payloadFactory media-type="xml">
<format>
<response>
<result>Unauthorized</result>
</response>
</format>
<args/>
</payloadFactory>
<send/>
</case>
错误：
TID: [0] [AM] [2014-12-02 08:16:30,852] ERROR {org.apache.synapse.core.axis2.Axis2Sender} - Unexpected error during sending message out {org.apache.synapse.core.axis2.Axis2Sender}
org.apache.axis2.AxisFault: The system cannot infer the transport information from the /devtest/1.0/users/admin URL.
at org.apache.axis2.description.ClientUtils.inferOutTransport(ClientUtils.java:81)
at org.apache.synapse.core.axis2.DynamicAxisOperation$DynamicOperationClient.executeImpl(DynamicAxisOperation.java:115)
at org.apache.axis2.client.OperationClient.execute(OperationClient.java:149)
at org.apache.synapse.core.axis2.Axis2FlexibleMEPClient.send(Axis2FlexibleMEPClient.java:482)
at org.apache.synapse.core.axis2.Axis2Sender.sendOn(Axis2Sender.java:59)
at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.send(Axis2SynapseEnvironment.java:338)
at org.apache.synapse.mediators.builtin.SendMediator.mediate(SendMediator.java:94)
at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:77)
at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:47)
at org.apache.synapse.config.xml.AnonymousListMediator.mediate(AnonymousListMediator.java:30)
at org.apache.synapse.config.xml.SwitchCase.mediate(SwitchCase.java:66)
at org.apache.synapse.mediators.filters.SwitchMediator.mediate(SwitchMediator.java:123)
at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:77)
at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:47)
at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:131)
at org.wso2.carbon.apimgt.gateway.handlers.ext.APIManagerExtensionHandler.mediate(APIManagerExtensionHandler.java:64)
at org.wso2.carbon.apimgt.gateway.handlers.ext.APIManagerExtensionHandler.handleRequest(APIManagerExtensionHandler.java:180)
at org.apache.synapse.rest.API.process(API.java:285)
at org.apache.synapse.rest.RESTRequestHandler.dispatchToAPI(RESTRequestHandler.java:83)
at org.apache.synapse.rest.RESTRequestHandler.process(RESTRequestHandler.java:64)
at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:220)
at org.apache.synapse.core.axis2.SynapseMessageReceiver.receive(SynapseMessageReceiver.java:83)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
at org.apache.synapse.transport.passthru.ServerWorker.processNonEntityEnclosingRESTHandler(ServerWorker.java:344)
at org.apache.synapse.transport.passthru.ServerWorker.run(ServerWorker.java:168)
at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
TID: [0] [AM] [2014-12-02 08:16:30,853] INFO {org.apache.synapse.mediators.builtin.LogMediator} - STATUS = Executing default 'fault' sequence, ERROR_CODE = 0, ERROR_MESSAGE = Unexpected error during sending message out {org.apache.synapse.mediators.builtin.LogMediator}