Cannot import into Label Studio: "load_tasks: No data found in DATA or in FILES"

We are trying to import annotated data from a remote machine under VPN within Label Studio, following the docs at the link
https://labelstud.io/guide/predictions.html#Import-OCR-pre-annotations
by running the following command
```bash
curl -X POST --noproxy '*' -H "Authorization: Token XXX" -F "file=X/file.json" http://localhost:8087/api/projects/{id}/import
```
found at the link
https://labelstud.io/api#operation/api_projects_import_create

in the POST requests section, which generates the following error:

Note: Unnecessary use of -X or --request, POST is already inferred.
* Trying ::1:8087...
* TCP_NODELAY set
* connect to ::1 port 8087 failed: Connection refused
* Trying 127.0.0.1:8087...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8087 (#0)
> POST /api/projects/3/import HTTP/1.1
> Host: localhost:8087
> User-Agent: curl/7.65.2
> Accept: */*
> Authorization: Token XXX
> Content-Length: 214
> Content-Type: multipart/form-data; boundary=------------------------05c24cb8b86fea83
>
* We are completely uploaded and fine
* Mark bundle as not supporting multiuse
< HTTP/1.1 400 Bad Request
< Date: Tue, 18 Jul 2023 14:34:18 GMT
< Server: WSGIServer/0.2 CPython/3.8.13
< Content-Type: application/json
< Allow: POST, OPTIONS
< Content-Length: 216
< Vary: Accept-Language, Cookie, Origin
< Content-Language: en-us
< X-Content-Type-Options: nosniff
< Referrer-Policy: same-origin
< Set-Cookie: sessionid=eyJ1aWQiOiJlYTJiM2Q2Yy04OGYzLTQyYWItOGYwZS1mZDFkMTQ4NTYyNTQiLCJvcmdhbml6YXRpb25fcGsiOjF9:1qLlmM:3DxZxbvdLe8iXR7QbVuuNsDqdE93JlVM3Lu70tT-kks; expires=Tue, 01 Aug 2023 14:34:18 GMT; HttpOnly; Max-Age=1209600; Path=/; SameSite=Lax
<
* Connection #0 to host localhost left intact
{"id":"b04c4a75-8116-46b4-acc9-41ee1c8aba0b","status_code":400,"version":"1.7.3","detail":"Validation error","exc_info":null,"validation_errors":{"non_field_errors":["load_tasks: No data found in DATA or in FILES"]}}