调用Dubbo服务报以下错误:RemotingException: message can not send, because channel is closed .

Caused by: com.alibaba.dubbo.remoting.RemotingException: message can not send, because channel is closed . url:dubbo://192.168.1.185:21954/com.tw.ei.business.agent.service.ReqBuinessAgentService?anyhost=true&application=consumer-engine&check=false&codec=dubbo&default.timeout=120000&dubbo=2.4.10&heartbeat=60000&interface=com.tw.ei.business.agent.service.ReqBuinessAgentService&methods=execute&pid=27587&retries=0&revision=reqappservice&side=consumer&timestamp=1399973540550&version=1.0.0 Caused by: com.alibaba.dubbo