ERROR: Unexpected error in launching a slave. This is probably a bug in Jenkins.
java.lang.NullPointerException
	at javax.mail.internet.InternetAddress.parse(InternetAddress.java:673)
	at javax.mail.internet.InternetAddress.parse(InternetAddress.java:633)
	at javax.mail.internet.InternetAddress.parse(InternetAddress.java:610)
	at org.jenkinsci.plugins.mailwatcher.MailWatcherMailer.send(MailWatcherMailer.java:120)
	at org.jenkinsci.plugins.mailwatcher.MailWatcherNotification.send(MailWatcherNotification.java:156)
	at org.jenkinsci.plugins.mailwatcher.WatcherComputerListener$Notification$Builder.send(WatcherComputerListener.java:176)
	at org.jenkinsci.plugins.mailwatcher.WatcherComputerListener.onOnline(WatcherComputerListener.java:99)
	at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:512)
	at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:349)
	at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:901)
	at hudson.plugins.sshslaves.SSHLauncher.access$400(SSHLauncher.java:126)
	at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:658)
	at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:642)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)