My email client cannot connect to the Secure SMTP server and returns an error "Unable to connect to SMTP Server". What should I do?

Check the opened port number.

You can connect to the SMTP server and request the available port number using the TELNET protocol.

• Click Start button
• Select 'Run...'
• Then type 'cmd' (no quotation marks) into the box and click 'OK'
• You should see an MS-DOS Prompt window appear. Type in the following command:
  
  telnet smtp-server.com 25
  (25 - is a port number, any port number is available from the range 25, 2525, 80, 8080, 574, 4000, 5000, 5001)
  
• Click OK to connect to the SMTP server If the connection is successful, a response from the mail server will appear in the TELNET window: ESMTP READY! WELCOME TO smtp-server.com!

Note: If you are unable to request the opened port number, use port 80 which is an alternate one.