Unrecognized SSL message, plaintext connection?

Preface

It was almost off work yesterday , A colleague posted an exception log in the Group , The contents are as follows

 Failed to send email :{}

javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
	at sun.security.ssl.InputRecord.handleUnknownRecord(InputRecord.java:710)
	at sun.security.ssl.InputRecord.read(InputRecord.java:527)
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:973)
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1403)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1387)
	at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:619)
	at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:393)
	at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:217)
	at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2160)
	at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:726)
	at javax.mail.Service.connect(Service.java:366)

Error reporting log is a function of sending email , He wondered if the email content contained escape characters , As a result, some emails can be sent normally , Some emails fail to be sent .

Nature of the problem

Look at this abnormal log , Like SSL Analytical problem , Services involving email sending have been upgraded to SSL 了 , The services have been launched , Sending email related codes is theoretically no problem , Later I thought of sending mail 25 Port and 465 port , Give it a try , Go to the integrated environment server and check the configuration of the mail server , The truth is clear ,66 The mailbox port on the server is 25 Of , and 169 The port on the server is 465 Of , Two nodes on the server , Request polling on both nodes , This explains , Why are some emails sent ok Of . It is clear that it will 25 Port to 465 Just ok 了 .

When troubleshooting , Occasional problems often occur , At this time, it is necessary to consider whether the environment has multiple nodes , Node environment 、 Is the configuration consistent . It has appeared before mq Misconfigured , Test environment mq Consume the message problem of the integrated environment , So be calm when troubleshooting problems , It depends on the actual error information in the exception log , So as to check the problem again .

Specific email support SSL Related information , You can see Email sending tool class