How to use mail destination with SAP SMTP server

Dear colleagues,

As part of the functionality in HCP, Email destination can be used to send mail to other people. It works pretty fine for gmail SMTP host with "smtp.gmail.com".

But how to use internal SAP email address with SAP SMTP server to sent mail in HCP?

For now, we have applied a mailbox with @sap.com, we want to use it as outgoing mailbox, and do the following configuration in HCP.

mail.smtp.host=mail.sap.corp

mail.host=mail.sap.corp

mail.user=xxx@sap.com

mail.password=xxx

mail.smtp.auth=true

mail.smtp.port=587

mail.smtp.starttls.enable=true

mail.transport.protocol=smtp

We deployed our application to HCP, but it always failed when send mail.

Error log:

javax.mail.MessagingException: Could not connect to SMTP host: mail.sap.corp, port: 587;

java.net.ConnectException: Connection timed out

Does anyone have experience on this topic about how to send mail from SAP email address in Java application deployed on HCP?

Thanks a lot.