How To Get Leads From Airtable To Smartlead Campaigns via API

I am creating an automation that creates records(leads) in an Airtable CRM when new leads are added to a specific table in another Base, gets the new one as a CSV and gets them into a smartlead campaign via an API call.

My automation seems to work fine up until the part of adding them to the smartlead campaign.


This is a screenshot of the full sceanrio.


And this is the setup of the smartlead api call modul


The actual JSON string being inputted

Let me know if more info is needed.