CKFinder 3 ASP.NET return 404 ckfinder/connector?command=GetFolders

I've installed CKFinder from NuGET on my ASP.NET 4.7 WEB Forms website. I've configured the web config, by adding the following keys in the appsettings:

<add key="ckfinderAllowedRole" value="*" />
<add key="ckfinderRoute" value="/ckfinder/connector" />

(I have not configured any authenticator at the moment)

In the web.config I have also the following config section for ckfinder:

 <ckfinder overwriteOnUpload="false" checkDoubleExtension="true" disallowUnsafeCharacters="false" secureImageUploads="true" checkSizeAfterScaling="true" xmlns="https://cksource.com/ckfinder-net/schema/CKFinderConnector.xsd">
<license name="" key="" />
<images maxWidth="1600" maxHeight="1200" quality="80">
    <sizes>
        <size name="small" width="480" height="320" quality="80" />
        <size name="medium" width="600" height="480" quality="80" />
        <size name="large" width="800" height="600" quality="80" />
    </sizes>
    <threshold pixels="80" percent="10" />
</images>
<thumbnails folder="thumbs" backend="CKFinderPrivate">
    <sizes>
        <size width="150" height="150" quality="80" />
        <size width="300" height="300" quality="80" />
        <size width="500" height="500" quality="80" />
    </sizes>
</thumbnails>
<backends>
    <!--
    This is special file system for private CKFinder data, it shouldn't be used for normal files.
    It shouldn't be modified unless CKFinder is hosted without access to the local file system.
    -->
    <backend name="CKFinderPrivate" adapter="local">
        <option name="root" value="App_Data" />
    </backend>
    <backend name="default" adapter="local">
        <option name="root" value="E:\myprojects\mywebsite\DefaultContents" />
        <option name="baseUrl" value="/DefaultContents/" />
    </backend>
</backends>
<resourceTypes>
    <resourceType name="Files" folder="files" allowedExtensions="7z,aiff,asf,avi,bmp,csv,doc,docx,fla,flv,gif,gz,gzip,jpeg,jpg,mid,mov,mp3,mp4,mpc,mpeg,mpg,ods,odt,pdf,png,ppt,pptx,pxd,qt,ram,rar,rm,rmi,rmvb,rtf,sdc,sitd,swf,sxc,sxw,tar,tgz,tif,tiff,txt,vsd,wav,wma,wmv,xls,xlsx,zip" backend="default" />
    <resourceType name="Images" folder="images" allowedExtensions="bmp,gif,jpeg,jpg,png" backend="default" />
</resourceTypes>
<accessControl>
    <role name="*" resourceType="*" folder="*" folderView="allow" folderCreate="allow" folderRename="allow" folderDelete="allow" fileView="allow" fileUpload="allow" fileRename="allow" fileDelete="allow" imageResize="allow" imageResizeCustom="allow" />
</accessControl>
<htmlExtensions>
    <extension name="html" />
    <extension name="htm" />
    <extension name="xml" />
    <extension name="js" />
</htmlExtensions>
<hideFolders>
    <folder name=".*" />
    <folder name="CVS" />
    <folder name="__thumbs" />
</hideFolders>
<hideFiles>
    <file name=".*" />
</hideFiles>
<plugins folder="plugins">
    <!--
  <plugin name="PluginName" />
  -->
</plugins>

where I've modified only the following settings:

<backend name="default" adapter="local">
    <option name="root" value="E:\myprojects\mywebsite\DefaultContents" />
    <option name="baseUrl" value="/DefaultContents/" />
</backend>

where E:\myprojects\mywebsite\DefaultContents is the folder where I want to store files.

when I browse to http://localhost:50393/CKFinderScripts/samples/full-page-open.html I get a 404:

The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

Requested URL      http://localhost:50393/ckfinder/connector?command=GetFolders&lang=it
Physical Path      E:\myproject\mywebsite\ckfinder\connector
Module     IIS Web Core
Notification       MapRequestHandler
Handler    StaticFile
Error Code     0x80070002

so it can't find anything at that route. Should I have to configure something else to make it work?

I'm running it locally from VS