Array
(
    [apikey] => 
    [email_address] => 
    [status] => subscribed
    [tags] => Array
        (
            [0] => 
        )

    [merge_fields] => Array
        (
            [FNAME] => 
            [LNAME] => 
        )

    [update_existing] => 1
)
string(206) "{"type":"https://mailchimp.com/developer/marketing/docs/errors/","title":"API Key Invalid","status":401,"detail":"Your request did not include an API key.","instance":"04b78026-b014-95c9-4e49-6a76ca774d46"}"
Mailchimp executed