GroupMail is a popular Windows application for sending newsletters and other bulk Emails. The application setup could be more intuitive, but if you follow these steps, you can successfully set up GroupMail to send Emails through your Easy-SMTP account.
The first step is to set up the basic account properties. We name this account profile ReachMail, then enter the name, company name, and Email addresses you'd like to use when sending through ReachMail.
The next step is to click the Delivery Options tab. Keep the Delivery Options as Standard, then enter ssrs.reachmail.net as the SMTP Server. Also, be sure to check the Requires Authentication box.
Now setup up the Authentication by clicking on the Setup button. On the next screen, be sure to set AUTH LOGIN (Default) and enter your Easy-SMTP username and password. The Username can be the Email address associated with the account. In some cases, you may need to use the ACCOUNT\username format
Click Ok, and the final step is to return to the Account Properties screen and click on the Advanced button. There set the SMTP Port to 587 and check the box for Server requires an SSL connection and make sure the drop-down next to it is set to STARTTS (default) as below
That's it. You should be able to go back to the Account Properties screen and click Test to test the connection.