Hi
We could connect to our slaves via ssh smoothly, until we installed the nodeofflinenotification plugin.
Once the plugin is installed,
*the connection is not established,
*there is no slave log at $JENKINS_HOME/logs/slaves/ created,
*[and a spinning wheel when trying to access the slave log from jenkins console, the log is not created anyway].

There were a bunch of plugins that were installed on our instance since the last successful slave connect, the new plugin which is causing this failure to connect is the nodeofflinenotification v 1.0.3 https://wiki.jenkins-ci.org/display/JENKINS/Node+Offline+Notification+Plugin

I've uninstalled the plugin and restarted our Jenkins, the slaves re-connect smoothly again.

I've categorized this as a 'Major' priority not for the functionality of the plugin but for the time and effort it could result in in identifying why the slaves are not connecting via ssh.

Thanks
Lata