Attribute required
Your request was missing an attribute that is required by the API.
Solution
If you're not using one of our API clients, check our documentation for the endpoint you're using and make sure the attributes are set up correctly in your request.
If you are using one of our API clients, check the rules for how to format attributes within your client. They are not always identical to how they would be sent if you weren't using an API client.
Learning resources
Tools
You can cut down on mistakes by using one of our clients. We offer clients for our API in these languages: