Grails configuration

Edit Subject

I have a Grails application deployed on Heroku and I'm trying to configure it to use the Heroku Sendgrid add-on.

Here is my Grails mail configuration:

grails {
mail {
host = "smtp.sendgrid.net"
port = 587
username = System.env.SENDGRID_USERNAME
password = System.env.SENDGRID_PASSWORD
props = ["mail.smtp.auth":"true"]
}
}

But when I try to send an email, I get the following exception:

java.net.ConnectException: Connection refused
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:327)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:193)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:180)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:384)
at java.net.Socket.connect(Socket.java:546)
at java.net.Socket.connect(Socket.java:495)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:284)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:227)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1672)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:525)
at javax.mail.Service.connect(Service.java:288)
at grails.plugin.mail.MailMessageBuilder.sendMessage(MailMessageBuilder.groovy:102)
at grails.plugin.mail.MailService.sendMail(MailService.groovy:39)
at MailGrailsPlugin$_configureSendMail_closure6.doCall(MailGrailsPlugin.groovy:149)