WhatsApp allows free-form messages (text, buttons, lists) only within 24 hours of the customer’s last message. Outside the window, only Meta-approved templates go out.
LiveShopia knows for every customer when she last wrote. Cart, reminder, expiry and confirmation all have a template version; if the window is closed, the bot sends the template automatically, and when the customer replies, the window opens and the conversation continues with buttons.
A message shows as “not sent” only when the template is not approved yet or the WhatsApp number is not connected. Channels shows the status of every template.
If it still does not work: check that the template is “approved”. If it is “pending”, messages to customers with a closed window will go out after approval.