How can I send a private message to a user with aspnet core SignalR?

I created a project x and I can't see where the error is. Everything works but the private message doesn't work. The link below is my sample project. In my real project, there is a feature called connectionToken in context on the client. How can I get the connectionToken value or why is it there?

**I use Redis backplane in my real project Example project link: https://github.com/fdevGit/SignalRExample

From the code you provide, use Clients.User() not Clients.Client().

Clients.User(...) takes a user identifier. Your parameter is connectionId which is a different concept and used with Clients.Client(...).

    public async Task SendMessageToUser(string user, string targetConnectionId, string message)
    {
        Console.WriteLine($"{Context.ConnectionId}-{targetConnectionId}-{message}");
        
        //await Clients.User(...)
        await Clients.Client(targetConnectionId).SendAsync("ReceiveMessageToUser", user, targetConnectionId, message);
    }

There is one more suggestion about the name of callback method. Return different method name in SendAsync().

   public async Task SendMessageToMe(string user, string message)
    {
        Console.WriteLine($"{Context.ConnectionId}-Caller-{message}");
        await Clients.Caller.SendAsync("ReceiveMessageToMe", user, message);
    }
    public async Task SendMessageToUser(string user, string targetConnectionId, string message)
    {
        Console.WriteLine($"{Context.ConnectionId}-{targetConnectionId}-{message}");
        await Clients.Client(targetConnectionId).SendAsync("ReceiveMessageToUser", user, targetConnectionId, message);
    }

Same change in char.js

connection.on("ReceiveMessageToMe", function (user, message) {
    var msg = message.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
    var encodedMsg = user + " says " + msg;
    var li = document.createElement("li");
    li.textContent = encodedMsg;
    document.getElementById("messagesList").appendChild(li);
});

connection.on("ReceiveMessageToUser", function (user, targetConnectionId, message) {
    var msg = message.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
    var encodedMsg = user + " says " + msg + " by " + targetConnectionId;
    var li = document.createElement("li");
    li.textContent = encodedMsg;
    document.getElementById("messagesList").appendChild(li);
});

Screenshots of Test