Agent went offline while building a ssh task
Asked by Clara Yuan:

The agent went offline while building. In the JOB,I use a "SSH Task" to connect to my vm from agent. During the ssh task, agent went offline.

the log of agent:

```
2020-08-19 22:45:52,712 WARN [0-BAM::nancafe2-bamboo-6::Agent:pool-3-thread-1] [AtlassianSshClient$AtlassianDefaultSshConfig] Illegal key size
2020-08-19 22:45:52,712 WARN [0-BAM::nancafe2-bamboo-6::Agent:pool-3-thread-1] [AtlassianSshClient$AtlassianDefaultSshConfig] Illegal key size
2020-08-19 22:45:52,724 WARN [0-BAM::nancafe2-bamboo-6::Agent:pool-3-thread-1] [AtlassianSshClient$AtlassianDefaultSshConfig] Illegal key size or default parameters
2020-08-19 22:45:52,724 WARN [0-BAM::nancafe2-bamboo-6::Agent:pool-3-thread-1] [AtlassianSshClient$AtlassianDefaultSshConfig] Disabling high-strength ciphers: cipher strengths apparently limited by JCE policy
2020-08-19 22:45:52,725 INFO [0-BAM::nancafe2-bamboo-6::Agent:pool-3-thread-1] [TransportImpl] Client identity string: SSH-2.0-SSHJ_0.27.0
2020-08-19 22:45:52,764 INFO [0-BAM::nancafe2-bamboo-6::Agent:pool-3-thread-1] [TransportImpl] Server identity string: SSH-2.0-OpenSSH_7.4
2020-08-19 23:00:04,933 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-19 23:00:04,999 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-19 23:00:08,600 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-19 23:00:21,609 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-19 23:06:04,170 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-19 23:37:02,684 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-19 23:57:33,759 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-20 00:00:00,975 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-20 00:00:00,997 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-20 00:00:01,016 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-20 00:03:02,190 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: invalidate executors: AllAgentsUpdatedEvent, agents known to be affected: []
2020-08-20 00:03:05,240 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-20 00:05:18,678 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: invalidate executors: AllAgentsUpdatedEvent, agents known to be affected: []
2020-08-20 00:18:05,041 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []
2020-08-20 00:24:37,570 INFO [AgentRunnerThread] [RemoteAgent] Starting Bamboo Remote Agent...
2020-08-20 00:24:37,570 INFO [AgentRunnerThread] [RemoteAgent] Starting application context...
2020-08-20 00:24:37,633 INFO [AgentRunnerThread] [RemoteAgent$1] Refreshing com.atlassian.bamboo.v2.build.agent.remote.RemoteAgent$1@3a0e4f40: startup date [Thu Aug 20 00:24:37 CST 2020]; root of context hierarchy
```

```
#another level of log 

INFO   | jvm 7    | 2020/08/20 00:18:05 | 2020-08-20 00:18:05,041 INFO [remoteEventRebroadcasterMessageListenerContainer-1] [RemoteEventRebroadcasterMessageListener] ExecutableQueueUpdate: addToQueue, agents known to be affected: []ERROR  | wrapper  | 2020/08/20 00:24:12 | JVM appears hung: Timed out waiting for signal from JVM.ERROR  | wrapper  | 2020/08/20 00:24:12 | JVM did not exit on request, terminatedSTATUS | wrapper  | 2020/08/20 00:24:12 | JVM exited in response to signal SIGKILL (9).INFO   | wrapper  | 2020/08/20 00:24:12 | JVM exited on its own while waiting to kill the application.STATUS | wrapper  | 2020/08/20 00:24:17 | Launching a JVM...INFO   | jvm 8    | 2020/08/20 00:24:18 | Wrapper (Version 3.2.3-atlassian-1) http://wrapper.tanukisoftware.orgINFO   | jvm 8    | 2020/08/20 00:24:18 |   Copyright 1999-2006 Tanuki Software, Inc.  All Rights Reserved.INFO   | jvm 8    | 2020/08/20 00:24:18 |INFO   | jvm 8    | 2020/08/20 00:24:18 | 2020-08-20 00:24:18,346 INFO [WrapperSimpleAppMain] [AgentBootstrap] Starting Agent Bootstrap using Java 1.8.0_91 from Oracle Corporation. Default charset: UTF-8, file name encoding: UTF-8
```

how to resolve it? or how to dig it?


Answers:
author: Mehmet A _Bloompeak_
body: Hi [@Clara Yuan](/t5/user/viewprofilepage/user-id/3355911) ,

There might be quite a number of underlying root causes. But you can start by checking the connection between agent and the server. Try below commands on the agent.

```
telnet bamboo_baseURL 8085
telnet bamboo_baseURL 54663
```

You can see further troubleshooting checks in below

<https://confluence.atlassian.com/bamkb/troubleshooting-remote-agent-216957427.html>