I a using the exact code here https://developers.sendinblue.com/reference/addcontacttolist-1 to add a user to a list. It all works, user is created/updated (if exists) then the user is added to the...

I'm using the Codeigniter framework and trying to integrate with SendInBlue's PHP API. Their PHP documentation is not super helpful and the setup instructions on Github not clear either. The doc s...