string(346) "{"type":"https://mailchimp.com/developer/marketing/docs/errors/","title":"Invalid Resource","status":400,"detail":"The resource submitted could not be validated. For field-specific details, see the 'errors' array.","instance":"8cd3b194-4dd9-a9b2-558b-59e479394a50","errors":[{"field":"email_address","message":"This value should not be blank."}]}" 37