You sent in a parameter that doesn't exist, isn't correct for the endpoint you're using, or has a bad value.
If you're not using one of our API clients, check our documentation for the endpoint you're using and make sure the parameters are set up correctly in your request.
If you are using one of our API clients, check the rules for how to format parameters within your client. They are not always identical to how they would be sent if you weren't using an API client.
You can cut down on mistakes by using one of our clients. We offer clients for our API in these languages: