Getting {code: 4, message: 'Invalid value passed for Invoice Date'} when trying to create bundle through web api

Getting {code: 4, message: 'Invalid value passed for Invoice Date'} when trying to create bundle through web api

Hi, I've been trying to use the web API to create bundles, using the following URL

using a POST request, with the following as my JSONString, passed through POSTMAN, 
with "Content-Type" : "application/json;charset=UTF-8"
{
    "reference_number": "TEST-BNDL-01",
    "date": "2017-01-05",
    "description": "TEST BUNDLE",
    "composite_item_id": 504366000000053250,
    "composite_item_name": "Coolblock sans GPU 140mm - Branded",
    "composite_item_sku": "CB-BRAND-NOGPU140MM",
    "quantity_to_bundle": 1,
    "line_items": [
        
        {
            
            
            "item_id": "2830884000005834246",
            "name": "Box 140mm - Branded",
            "description": "",
            "quantity_consumed": 0,
            "units": "units",
            "account_id": "2830884000000079020",
            "account_name": "Finished Goods",
            "warehouse_id": "2830884000000216076",
            "warehouse_name": "First Block",
            "rate": 404
      
        }
    ],
    "is_completed": true
},

And I keep getting the following error:
{ code: 4, message: 'Invalid value passed for Invoice Date' }.

If anyone could help point me in the right direction, it'd be appreciated.