It's often useful to test an email server manually - to ensure the port is open and redirected properly, and also that the server is delivering messages to the mailbox correctly.

Here is how to send an email manually with telnet:

Open a command prompt on the PC you will send the test email from

telnet server.server.com 25
HELO jaytag.co.uk (response will be 250 OK)
MAIL FROM:dmcmillan@jaytag.co.uk (response should be 250 OK - mail from dmcmillan@jaytag.co.uk)
RCPT TO:james@stephenrjames.com (response should be 250 OK - Recipient james@stephenrjames.com)
DATA (response should be 354 Send data. End with CRLF.CRLF)
Test Email!
(line break)
.
(line break)
QUIT

A successful delivery will look something like this: 250 OK