400

Array
(
    [name] => INVALID_REQUEST
    [message] => Request is not well-formed, syntactically incorrect, or violates schema.
    [debug_id] => 1415ab75b2ae3
    [details] => Array
        (
            [0] => Array
                (
                    [field] => /subscriber/email_address
                    [value] => 
                    [location] => body
                    [issue] => INVALID_PARAMETER_SYNTAX
                    [description] => The value of a field does not conform to the expected format.
                )

        )

    [links] => Array
        (
            [0] => Array
                (
                    [href] => https://developer.paypal.com/docs/api/v1/billing/subscriptions#INVALID_REQUEST
                    [rel] => information_link
                    [method] => GET
                )

        )

)
0: