Many SMTP mail servers require that senders authenticate themselves before having access to their mail server. To add authentication to your GroupMail sender account, click Tools/Account Manager and click “Modify” for the account you have configured. Check the “Requires Authentication” box under the SMTP server address and click “Setup”. Use SMTP Authentication (outbound) and add your user name (usually your email address) and password for the email address you are sending from.
After entering these details, click OK and Ok again on the Account Properties screen to save those changes.
For more information, watch my video tutorial, How to Configure Your GroupMail Sender Account.
