The ActiveCampaign email marketing add-on adds an option for your customers to join your ActiveCampaign email list during checkout.
Installation Instructions for ActiveCampaign
After purchasing, download the add-on to your computer. The plugin will be in the form of a zip file. Login to your WordPress admin and go to Plugins. Then click Add New. Then click Upload. Click Choose File and browse to the add-on file on your computer. Finally click Install Now.
Be sure to Activate the plugin after the upload is complete.
Configuration Instructions for ActiveCampaign
Locate the settings for this add-on via WordPress admin --> Downloads --> Settings --> Misc. Then enter your API URL, API Key, and List ID for ActiveCampaign. Finally set a Checkout Label and click Save Settings.
Emails are not added to a list selected in the Download's Per-Product Lists
Most likely, the customer did not opt-in upon checkout. If opt-in is not selected, then an email will not be added to the default list or the per-product list(s). If opt-in is selected at checkout, the email address will be added to the default list and any other per-product lists that might be selected.