我正在使用ganymed-ssh-2 Java库创建从一个AWS EC2到另一个AWS EC2（在同一个VPC中）的连接，并且'connect（）'命令给出以下错误：

java.io.IOException: Key exchange was not finished, connection is closed.
    at ch.ethz.ssh2.transport.KexManager.getOrWaitForConnectionInfo(KexManager.java:75)
    at ch.ethz.ssh2.transport.TransportManager.getConnectionInfo(TransportManager.java:169)
    at ch.ethz.ssh2.Connection.connect(Connection.java:759)
    at ch.ethz.ssh2.Connection.connect(Connection.java:628)
    at bravura.autoperf.executor.SSHExecutor.connectTo(SSHExecutor.java:156)
    at bravura.autoperf.executor.SSHExecutor.runRemoteSSHCommand(SSHExecutor.java:57)
    at bravura.autoperf.executor.SSHExecutor.runRemoteSSHCommand(SSHExecutor.java:141)
    at bravura.autoperf.util.Utilities.runCommandRepeatedly(Utilities.java:614)
    at bravura.autoperf.test.Server.getServerDetails(Server.java:233)
    at bravura.autoperf.test.Server.<init>(Server.java:127)
    at bravura.autoperf.test.Server.<init>(Server.java:65)
    at bravura.autoperf.util.Utilities.getClientServer(Utilities.java:499)
    at bravura.autoperf.manager.RunSetupManager.<init>(RunSetupManager.java:69)
    at bravura.autoperf.manager.ExecutionManager.runTests(ExecutionManager.java:171)
    at bravura.autoperf.manager.ExecutionManager.main(ExecutionManager.java:64)
Caused by: java.io.IOException: Cannot negotiate, proposals do not match.
    at ch.ethz.ssh2.transport.ClientKexManager.handleMessage(ClientKexManager.java:123)
    at ch.ethz.ssh2.transport.TransportManager.receiveLoop(TransportManager.java:572)
    at ch.ethz.ssh2.transport.TransportManager$1.run(TransportManager.java:261)
    at java.lang.Thread.run(Thread.java:748)

调用代码：

Connection connection = new Connection(host);
    connection.connect();

这是在有机会调用“authenticateWithPublicKey（）”方法之前。
已为VPC CIDR范围（两个示例均在该范围内）的22端口流量开放NACL和相关安全组。路由表将所有VPC CIDR流量路由到本地。
我可以手动SSH没有问题。
(OS是Amazon Linux 2 fwiw）
谢谢你的帮助。