SimpleEmail forces SMTP to port 465 - email

Question

I've been trying to send an email programmatically from the server using SimpleEmail. I use Kotlin. So far it always leads to an error that seems to only use port 465 despite setting it to a different port. I've been trying to find out why it does this but I have not seen any point this out.
SimpleEmail().apply {
hostName = "smtp.gmail.com"
setSmtpPort(587)
setAuthenticator(DefaultAuthenticator("**email**", "**password**"))
setSSLOnConnect(true)
setFrom("**email**")
subject = "TEST"
setMsg("TEST")
addTo(email)
}.send()
The error:
org.apache.commons.mail.EmailException: Sending the email to the following server failed : smtp.gmail.com:465

Answer 1

A little late, but maybe it still helps someone.
Ports 25 and 587 use TLS, while port 465 uses SSL. If you setSSLOnConnect, then it forces the port 465, because that is the SSL port.
Instead, you have to use setStartTLSEnabled and optionally setStartTLSRequired to true, but not setSSLOnConnect.

Answer 2

hostName should be = "smtp.googlemail.com" but not "smtp.gmail.com", if it does not work, check the gmail settings for access to smpt.
const val myEmail = "test#gmail.com"
const val myPassword = "test"
const val receivingAddress = "test"
fun main(args: Array<String>) {
SimpleEmail().apply {
hostName = "smtp.googlemail.com"
isSSLOnConnect = true
subject = ("subject")
setSmtpPort(465)
setAuthenticator(DefaultAuthenticator(myEmail, myPassword))
setFrom(myEmail)
setMsg("message")
addTo(receivingAddress)
}.send() // will throw email-exception if something is wrong
}