Why Do I get an error when posting a new ad (item)?

I'm trying to make a post request in order to submit a new item (ad), but. But when I do so I get a 400 error: http_status: 400, message: "Unknown field name 'url'", message_code: 'api.action.bad_request.null'

This is the code:

const url = 'https://backstage.taboola.com/backstage/api/1.0/'+accountID+'/campaigns/'+cID+'items/'; const options = { method: 'POST', headers: { Authorization: "Bearer" + await getToken(), Accept: 'application/json', 'Content-Type': 'application/json'}, body: JSON.stringify({ url: landingPage, thumbnail_url: image, title: adTitle })

} const respose = await fetch(url, options);