[15:16] WebSocket connected to wss://stream.bybit.com/v5/public/spot
[15:16] Sending message: {"op":"subscribe","req_id":2,"args":["orderbook.50.PIEVERSEUSDT"]}
...
[15:16] Sending message: {"req_id":50869,"op":"ping"}
[15:17] On message: {"success":true,"ret_msg":"pong","conn_id":"d49d7dtpfljs93ea6ppg-3esan","req_id":"50869","op":"ping"}
[15:18] The remote party closed the WebSocket connection without completing the close handshake.

using ccxt.pro;
using Newtonsoft.Json.Linq;

class Program
{
    static async Task Main()
    {
        var exchange = new Bybit();
        var markets = await exchange.LoadMarkets();

        JObject marketsObject = JObject.FromObject(exchange.markets);
        var spotSymbols = marketsObject
            .Properties()
            .Where(p => (string)p.Value["type"] == "spot")
            .Select(p => p.Name)
            .ToList();
        Console.WriteLine($"[{DateTime.Now:HH:mm}] Found {spotSymbols.Count} spot symbols.");

        var tasks = spotSymbols.Select(symbol => WatchOrderBookLoop(exchange, symbol)).ToArray();
        await Task.WhenAll(tasks);
    }

    private static async Task WatchOrderBookLoop(Bybit exchange, string symbol)
    {
        while (true)
        {
            try
            {
                var ob = await exchange.WatchOrderBook(symbol);
            }
            catch (Exception ex)
            {
                //after 2 min: (The remote party closed the WebSocket connection without completing the close handshake.)
                Console.WriteLine($"[{DateTime.Now:HH:mm}] Error on {symbol}: {ex}");
                await Task.Delay(1000);
            }
        }
    }
}