[Close Position Using rest API]

If anyone is still having this problem, the answer is to use the POST method on your httpClient obj (whatever you're using) and set a header value. ("_method": "DELETE")

It needs to be POST because you're adding a request body, which isn't supposed to work with the DELETE verb.

So a request will look like this:

Method: POST

POST body:
{
    "dealId": "<deal id>",
    "direction": "SELL",
    "size": "1",
    "orderType": "MARKET",
}
All the rest could be null

Headers:
X-IG-API-KEY: <your api key>
X-SECURITY-TOKEN: <your token from logging in>
CST: <your cst token from logging in>
Content-Type: application/json
Version: 1
_method: DELETE

Hope this helps