Connect Klaviyo

Create an API key with Full Access for Lists, Profiles and Subscriptions, see here: How to create a private API key | Klaviyo Help Center
Get the list id where the leads should be added to, see here: How to find a list ID | Klaviyo Help Center
Send the Newsletter System name, the API key and the list ID to Sovendus

Create an API key with Full Access for Lists, Profiles and Subscriptions, see here: How to create a private API key | Klaviyo Help Center
Get the list id where the leads should be added to, see here: How to find a list ID | Klaviyo Help Center
Send the Newsletter System name, the API key and the list ID to Sovendus