What causes and how to resolve EntryPointNotFoundException in Unity? - unity3d

Question

I'm very new to unity. I'm trying to play in unity the example room scene from livekit https://github.com/livekit/client-sdk-unity-web (Livekit enables webRTC for unity WebGL project) but I can not because I receive an EntryPointNotFoundException whenever there is a DLLImport Internal in the code.
Here is an example of the error I get :
Here is an extract code from JSRef where line 92 is:
[Preserve]
internal JSRef(JSHandle handle)
{
NativeHandle = handle;
// We add the instantiated object into the cache se we can retrieve it later if not garbage collected.
// Note that if JSRef has been garbage collected, it doesn't mean that the key doesn't exists on this map ( Finalizer is unpredictable )
Cache[handle.DangerousGetHandle()] = new WeakReference<JSRef>(this);
}
internal JSRef() : this(JSNative.NewRef()) //this is line 92
{
}
And the code where newRef is in the file JSNative:
[DllImport("__Internal")]
internal static extern JSHandle NewRef();
and this is the code for JSHandle :
public class JSHandle : SafeHandleZeroOrMinusOneIsInvalid
{
private JSHandle() : base(true)
{
}
internal JSHandle(IntPtr ptr, bool ownsHandle) : base(ownsHandle)
{
SetHandle(ptr);
}
protected override bool ReleaseHandle()
{
return JSNative.RemRef(handle);
}
}
Please help me, I've looked on Google and other posts on StackOverflow but I don't know what to do....