send an email using play

I am trying to use Mail (play.libs.Mail)

In my application.conf I have added:
mail.smtp.host=xxx
mail.smtp.port=23

It seems the parameter mail.smtp.port is not used as I get the error below. The port 25 is used instead of the port 23. What can I do?

A mail error occured : Error while sending email

play.exceptions.MailException: Error while sending email
 at play.libs.Mail$1.run(Mail.java:209)
Caused by: javax.mail.MessagingException: Could not connect to SMTP host: xxx, port: 25;
  nested exception is:
 java.net.ConnectException: Connection timed out
 at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1391)
 at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:412)
 at javax.mail.Service.connect(Service.java:288)
 at javax.mail.Service.connect(Service.java:169)
 at play.libs.Mail$1.run(Mail.java:205)
Caused by: java.net.ConnectException: Connection timed out
 at java.net.PlainSocketImpl.socketConnect(Native Method)
 at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
 at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
 at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
 at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
 at java.net.Socket.connect(Socket.java:519)
 at java.net.Socket.connect(Socket.java:469)
 at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:233)
 at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:189)
 at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1359)
 ... 4 more