Since the new website features a new activation server, all the applications need to be updated to point to it. So you must download the latest version to activate it.
This is a free upgrade for Version 6 ShotPut Pro customers. You should be able to click "Check for Updates" within the software to download v2018.1.
When you run it, it should automatically activate, replacing the ShotPut Pro 6 on your computer. Please note this version is named "ShotPut Pro" only--not "ShotPut Pro 6".
If the automatic update isn't working, you can manually download the software. To download, go to the website www.imagineproducts.com and log in under ACCOUNT (upper right). Then choose VIEW LICENSES from the Account menu. You'll see the list of your apps and the download link is on the right.
With the new system you can still activate simply by entering your email and account password. Doing that will activate the first item on your list.
OR, you can copy and paste in the assigned "serial number" for a specific license and activate that specific one.