Website returns 482 invalid cookie

Question

After I load a url with the browser, I'm sending a request follows:

var frame = browser.GetMainFrame();
var request = frame.CreateRequest();

request.Url = "urlhere";
request.Method = "PUT";

NameValueCollection headers = new NameValueCollection();
headers.Add("Host", "hosthere");
//etc...
request.Headers = headers

request.InitializePostData();
var element = request.PostData.CreatePostDataElement();
element.Bytes = Encoding.UTF8.GetBytes("mydata") ;
request.PostData.AddElement(element);

frame.LoadRequest(request);

However I get the error:

{"message":"Invalid Cookie", "code":482}

CefSharp is initialized as follows:

CefSettings settings = new CefSettings();
settings.CefCommandLineArgs.Add("enable-npapi", "1");

Cef.Initialize(settings);

I also have multiple browsers, which are created as follows:

var contextSettings = new RequestContextSettings();
contextSettings.CachePath = cachePath;

var browser = new ChromiumWebBrowser(urlStr)
{
    BrowserSettings = new BrowserSettings()
    {
        Javascript = CefState.Enabled,
        Plugins = CefState.Enabled,
    },
    RequestContext = new RequestContext(contextSettings),
    RequestHandler = new CustomRequestHandler,
};

As shown in the snippet above, I'm using a cache path for each browser session. Wouldn't the cookies be located there?

How do I retrieve the cookies and set them for this request?

Also, I'm not setting the Content-Length header. Is this set by cefSharp automatically when sending a Post request?

EDIT

To get the cookies I'm doing:

var cookies = await Cef.GetGlobalCookieManager().VisitAllCookiesAsync();

However the list always contains 0 cookies.

I've also cleared the cache, and once the page was loaded, I noticed that a Cookies file was created. Editing it (looks like a SQLite3 database) shows that cookies have been actually created and there are those that I'm interesed in.

So why isn't the manager getting the cookies?