Why is SignalR Core running in a service being ignored?

Question

ASP.NET

register service:

var provider = services.BuildServiceProvider();
            using (var scope = provider.CreateScope())
            {
                IHubContext<CrashHub> crashHub = (IHubContext< CrashHub > )provider.GetService<IHubContext<CrashHub>>();
                GamesContext сrashService = new GamesContext(connection);
                services.AddSingleton<IHostedService, CrashService>(s => new CrashService(crashHub, сrashService, Configuration));
            }

line

IHubContext<CrashHub> crashHub = (IHubContext< CrashHub > )provider.GetService<IHubContext<CrashHub>>();

is responsible for getting the hub context, then I pass it to my service.
This is what the hub constructor looks like:

public CrashService(IHubContext<CrashHub> hubContext, GamesContext db, IConfiguration configuration)
        {
            _db = db;
            _hubContext = hubContext;
        }

There are no errors, everything starts. I'm trying to send a message

await _hubContext.Clients.All.SendAsync("wait", 2);

, but it is not sent. What to do about it, what could be the reason?