JIRA Outgoing Mail Fails
Platform Notice: Server and Data Center Only. This article only applies to Atlassian products on the server and data center platforms.
When JIRA triggers an outgoing mail and mails are not sent however a look at the outgoing mail configuration shows the outgoing mail configuration is correct.
The following appears in the atlassian-jira-outgoing-mail
Caused by: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 587; nested exception is: javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection? at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2056) [javax.mail-1.5.4.jar:1.5.4] at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:697) [javax.mail-1.5.4.jar:1.5.4] at javax.mail.Service.connect(Service.java:386) [javax.mail-1.5.4.jar:1.5.4] at javax.mail.Service.connect(Service.java:245) [javax.mail-1.5.4.jar:1.5.4] at javax.mail.Service.connect(Service.java:194) [javax.mail-1.5.4.jar:1.5.4] at com.atlassian.mail.server.impl.SMTPMailServerImpl.sendWithMessageId(SMTPMailServerImpl.java:174) [atlassian-mail-2.5.16.jar:?] ... 25 more
The configured mail server has TLS security in place, hence you would need to select this option for JIRA to be able to use it for sending mails.
Check the TLS option in the outgoing mail configuration page.
Confirm with your mail server admin that what you have configured is what is expected by the mail server.