Why is my Attentive form not behaving as expected?
When redirecting a custom or third party form to a Klaviyo list, it is expected that the form will adhere to your list’s double opt-in behavior. By default, Attentive forms will use a members endpoint from the V2 list API. This is equivalent to uploading a CSV of opt-ins into a Klaviyo list and we would not trigger a double opt-in message to be sent, even if it is enabled at the list level.
In order to have your Attentive form adhere to the list opt-in settings, the endpoint needs to be changed to the subscribe endpoint. We will then treat it as though the user signed up through a signup form and respect the opt-in settings. This redirect must be done by Attentive. You should reach out to Attentive to switch these endpoints on the Attentive end.