Jira notification emails fail to be sent due to the "Unrecognized SSL message" error
Platform Notice: Data Center Only - This article only applies to Atlassian products on the Data Center platform.
Note that this KB was created for the Data Center version of the product. Data Center KBs for non-Data-Center-specific features may also work for Server versions of the product, however they have not been tested. Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Problem
Jira notifications emails are not and the following appears in the atlassian-jira-outgoing-mail.log file:
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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 moreEnvironment
Jira Server/Data Center on any version from 8.0.0.
Cause
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.
Resolution
Check the TLS option in the outgoing mail configuration page.
ℹ️Confirm with your mail server admin that what you have configured is what is expected by the mail server.
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