Jenkins Email sending fails

I set up the JENKINS Editable Email notification for my project with trigger for all builds.

the build runs successfully but the emails does not send. The follwing is the result in the console output.

BUILD SUCCESSFUL
Total time: 43 seconds
Email was triggered for: Always
Sending email for trigger: Always
Sending email to: chauhanheena@gmail.com
Connection error sending email, retrying once more in 10 seconds...
Connection error sending email, retrying once more in 10 seconds...
Failed after second try sending email
Finished: SUCCESS

Solution：

　　Make sure SMTP server is configured under "Manage Jenkins" -> "Configure System" -> "Extended E-mail Notification"

　　Note also that depending on your plug-in set up, you may have another place to configure SMTP server. For example under "Manage Jenkins" -> "Configure System" -> E-mail Notification.

　　That is not needed for this particular plug-in but it may lead you think you have everything done, while it is not :)