Hi,

I believe there is a bug with the "Use TLS" support that was added recently. With this option enabled, setting the SMTP port has no effect and 587 is always used.

I believe line 333 in the ExtendedEmailPublisherDescriptor is the issue here https://github.com/jenkinsci/email-ext-plugin/blob/master/src/main/java/hudson/plugins/emailext/ExtendedEmailPublisherDescriptor.java#L333 and it should be the same as line 308 but I am not able to easily test this at the moment.

I've set the priority on this ticket to minor as I think this can be worked around by not setting this option and using the method that people used before this option was added but I haven't tested this workaround.

I've included a log below showing that it's sending to port 587 while in the config view it's clearly set to 26.

11:11:23.666 Sending email to: <EMAIL_ADDRESS>
11:11:23.666 DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle]
11:11:23.669 DEBUG SMTP: useEhlo true, useAuth false
11:11:23.669 DEBUG SMTP: trying to connect to host "<SMTP SERVER>", port 587, isSSL false
11:11:23.670 Connection error sending email, retrying once more in 10 seconds...
11:11:33.670 DEBUG SMTP: useEhlo true, useAuth false
11:11:33.671 DEBUG SMTP: trying to connect to host "<SMTP SERVER>", port 587, isSSL false
11:11:33.671 Connection error sending email, retrying once more in 10 seconds...
11:11:43.672 Failed after second try sending email

Thanks,
Kian