It's hard to know exactly what the issue is without a response body. It's possible that your Content-Type and Accept headers are not necessary and are causing the issue.
You can use the Uploading Contacts to a Contact List Javascript tutorial as a reference to show how this is achieved in Javascript.
The request's content-type must be "multipart/form-data" and the body must be encoded accordingly (i.e. FormData).
The link Ronan has mentioned above is doing this with javascript/jquery. You should check how to do the equivalent with axios.
We do not have a node example for the upload of contact list.
But you can possibly check this web page that describes how to use Axios with Multipart Form Data.