I'm not too experienced with filing bug reports and I don't know how to make a patch file, so I'll just do it like this. I also don't know whether this is fixed already in an unreleased version... But I just hope I can help.
On line 1240 of Email.java in version 1.2 of Commons Email, the message of the exception is extended with this.getSmtpPort. This is incorrect; this should be something like:
Else it results in questions like http://stackoverflow.com/questions/13951322/javamail-email-commons-empty-message-gives-strange-error