Connection refused implies that either your smtp settings are incorrect or your server is blocking it.
First, I'd double check the server address is correct. Also, if you need a username/password, ensure that's correct
Next, log on to the Manager and try to telnet port 25. If there's an error there, it's a firewall issue, you may need to ask your firewall team to make an exception.
If you can telnet the port, then it's a more interesting issue.
If you're attempting to use a google account, your server URL would be 'smtp.gmail.com', in the office our installations are configured to use SSL so the full URL is 'smtps://smtp.gmail.com:465', Username is your full gmail email, and password is obviously your password.
BTW - you will not be able to use the gmail account logscape includes in the default config. Google will block the request coming from unfamiliar IP's/Regions. Instead - you can create your own google account to use unstead.