Some customers get confused when asked to provide their SMTP outgoing server address when configuring GroupMail for delivery. To ease this confusion, I put a spreadsheet together with the incoming and outgoing server addresses most often used for sending email. If yours isn’t listed, let us know and we’ll help.
Read Outgoing Mail Server Addresses for [...]

To enter Authentication into GroupMail, simply go to Tools Menu, Account Manager, select your account and press Modify.
Then go to the Delivery Options Tab, check on the option ‘Requires Authentication’ and press Setup.
Here you can enter your details.