我正在尝试使用openstack4j，我遇到了一个我不知道可能导致什么问题的问题。
对云的身份验证进展顺利：
OSClient os = OSFactory.builder()
.endpoint("http://xxx.xxx.xxx.xxx:yyyyy/v2.0")
.credentials(username,password)
.tenantName("admin")
.perspective(Facing.PUBLIC)
.authenticate();
然而，一旦os被实例化，我尝试运行以下行：
List<? extends Flavor> flavors = os.compute().flavors().list();
我得到一个ConnectionException {message = java.net.ConnectException：Connection timed out：connect，status = 0}
导致这种情况的原因是什么？
提前致谢。
堆栈追踪：
Exception in thread "main" ConnectionException{message=java.net.ConnectException: Connection timed out: connect, status=0}
at org.openstack4j.connectors.jersey2.HttpExecutorServiceImpl.invoke(HttpExecutorServiceImpl.java:58)
at org.openstack4j.connectors.jersey2.HttpExecutorServiceImpl.execute(HttpExecutorServiceImpl.java:33)
at org.openstack4j.core.transport.internal.HttpExecutor.execute(HttpExecutor.java:51)
at org.openstack4j.openstack.internal.BaseOpenStackService$Invocation.execute(BaseOpenStackService.java:178)
at org.openstack4j.openstack.internal.BaseOpenStackService$Invocation.execute(BaseOpenStackService.java:172)
at org.openstack4j.openstack.compute.internal.FlavorServiceImpl.list(FlavorServiceImpl.java:32)
at com.mycompany.app.my_app.OpenStackCom.authOpenStack(OpenStackCom.java:127)
at com.mycompany.app.my_app.App.main(App.java:18)
Caused by: javax.ws.rs.ProcessingException: java.net.ConnectException: Connection timed out: connect
at org.glassfish.jersey.client.HttpUrlConnector.apply(HttpUrlConnector.java:229)
at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:224)
at org.glassfish.jersey.client.JerseyInvocation$1.call(JerseyInvocation.java:656)
at org.glassfish.jersey.client.JerseyInvocation$1.call(JerseyInvocation.java:653)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:424)
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:653)
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:388)
at org.openstack4j.connectors.jersey2.HttpCommand.execute(HttpCommand.java:86)
at org.openstack4j.connectors.jersey2.HttpExecutorServiceImpl.invokeRequest(HttpExecutorServiceImpl.java:65)
at org.openstack4j.connectors.jersey2.HttpExecutorServiceImpl.invoke(HttpExecutorServiceImpl.java:56)
... 7 more
Caused by: java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.net.HttpURLConnection.getResponseCode(Unknown Source)
at org.glassfish.jersey.client.HttpUrlConnector._apply(HttpUrlConnector.java:321)
at org.glassfish.jersey.client.HttpUrlConnector.apply(HttpUrlConnector.java:227)