Etsy API - OPTIONS failing before POST to guest cart

Question

I'm trying to use the Etsy API for an application that uses guest carts, and I'm encountering an error when I try to POST to https://openapi.etsy.com/v2/guests/<user's current guest ID>/carts?api_key=<my API key> . I'm sending a JSON object that contains guest_id and listing_id (as per the Etsy documentation ), as well as filling in the guest ID and API key in the URL (as you can see above).

I'm using Axios to make the POST request, and as part of the default setup, Axios performs a preflight OPTIONS request to verify that a POST is possible at the given URL. I'm getting a 400 error upon this OPTIONS request, and the POST isn't even being sent.

Is there a way around this? I was under the impression that these OPTIONS requests were a necessary part of the request chain, hence why Axios automatically sends one.

I'm using Vue.js and running a local server via the Vue CLI, so the request is coming from http://localhost , and here's the actual error.