If you are running a test or evaluation Jira instance, or testing changes that you have made to your configurations, you might not want to flood your users with test emails. The easiest way for you to disable all outgoing emails is by just clicking on the Disable Outgoing Mail button. This will stop Jira from sending emails as a result of issue updates. Once you are ready to send emails again, you can click on the Enable Outgoing Mail button.