CentOS 7 Graylog version: 4.1.2+20cd592, codename *Noir* Java version: openjdk version 1.8.0_292
The error is like this:
Error: Notification has email recipients and is triggered, but sending emails failed. Sending the email to the following server failed : FQDN:25 The Graylog server encountered an error while trying to send an email. This is the detailed error message: org.apache.commons.mail.EmailException: Sending the email to the following server failed : FQDN:25 (javax.mail.MessagingException: Could not convert socket to TLS; nested exception is: javax.net.ssl.SSLHandshakeException: Remote host terminated the handshake)
Researching and googling showed that it’s javamail’s problem: apparently it uses TLS 1.1 by default which is prohibited by the mail server.
So, here’s the question: How do I make it use only 1.2 and higher? What’s the most correct way from Graylog’s point of view?