Missing required params

I'm trying to create a task with the POST /api/task resource and send the following JSON data:

```
{
    "name":"TYS-123456 issue name",
    "description":"some description",
    "project_id":123456,
    "tasklist_id":654321
}
```
After sending this I get a "Missing required params: name, tasklist_id or project_id". However, all three parameters are given and are valid.