阿里云物联网平台服务端订阅

出现以下错误：
2019-05-09 10:53:15 [nioEventLoopGroup-2-1] INFO c.a.o.iot.api.http2.IotHttp2Client - connection status changed, connection: 771bd824, status: CREATING
2019-05-09 10:53:15 [nioEventLoopGroup-2-1] INFO c.a.o.iot.api.http2.IotHttp2Client - receive setting, connection: 771bd824, subscription count : 8
2019-05-09 10:53:15 [nioEventLoopGroup-2-1] INFO c.a.o.iot.api.http2.IotHttp2Client - connection status changed, connection: 771bd824, status: CREATED
2019-05-09 10:53:30 [nioEventLoopGroup-2-1] INFO c.a.o.iot.api.http2.IotHttp2Client - connection status changed, connection: 771bd824, status: CLOSED
Exception in thread "main" com.aliyun.openservices.iot.api.exception.IotClientException: com.aliyuncs.exceptions.ClientException: SDK.ServerUnreachable : Server unreachable: java.net.SocketException: Unexpected end of file from server

at com.aliyun.openservices.iot.api.auth.handler.accesskey.AccessKeyAuthHandler.updateToken(AccessKeyAuthHandler.java:74)
at com.aliyun.openservices.iot.api.auth.handler.accesskey.AccessKeyAuthHandler.getAuthParams(AccessKeyAuthHandler.java:56)
at com.aliyun.openservices.iot.api.http2.IotHttp2Client.authHeader(IotHttp2Client.java:158)
at com.aliyun.openservices.iot.api.message.impl.MessageClientImpl.sendAuth(MessageClientImpl.java:95)
at com.aliyun.openservices.iot.api.message.impl.MessageClientImpl.doConnect(MessageClientImpl.java:107)
at com.aliyun.openservices.iot.api.message.impl.MessageClientImpl.connect(MessageClientImpl.java:300)
at com.aliyun.iot.demo.H2Client.main(H2Client.java:36)

Caused by: com.aliyuncs.exceptions.ClientException: SDK.ServerUnreachable : Server unreachable: java.net.SocketException: Unexpected end of file from server

at com.aliyuncs.DefaultAcsClient.doAction(DefaultAcsClient.java:295)
at com.aliyuncs.DefaultAcsClient.doAction(DefaultAcsClient.java:207)
at com.aliyuncs.DefaultAcsClient.doAction(DefaultAcsClient.java:100)
at com.aliyuncs.DefaultAcsClient.getAcsResponse(DefaultAcsClient.java:144)
at com.aliyun.openservices.iot.api.auth.handler.accesskey.AccessKeyAuthHandler.updateToken(AccessKeyAuthHandler.java:68)
... 6 more