---> System.TimeoutException: A timeout occured after 30000ms selecting a server using CompositeServerSelector\{ Selectors = MongoDB.Driver.MongoClient+AreSessionsSupportedServerSelector, LatencyLimitingServerSelector{ AllowedLatncyRange = 00:00:00.0150000 } }. Client view of cluster state is \{ ClusterId : "1", ConnectionMode : "Automatic", Type : "Unknown", State : "Disconnected", Servers : [{ ServerId: "{ ClusterId : 1, EndPoint : "Unspecified/<SERVER HOSTNAME>:27017" }", EndPoint: "Unspecified/<SERVER HOSTNAME>:27017", ReasonChanged: "Heartbeat", State: "Disconnected", Type: "Unknown", HeartbeatException: "MongoDB.Diver.MongoConnectionException: An exception occurred while opening a connection to the server.
 ---> System.PlatformNotSupportedException: Sockets on this platform are invalid for use after a failed connection attempt.
 at System.Net.Sockets.Socket.ThrowMultiConnectNotSupported()
 at System.Net.Sockets.Socket.BeginConnect(String host, Int32 port, AsyncCallback requestCallback, Object state)
 at MongoDB.Driver.Core.Connections.TcpStreamFactory.ConnectAsync(Socket socket, EndPoint endPoint, CancellationToken cancellationToken)
 at MongoDB.Driver.Core.Connections.TcpStreamFactory.CreateStreamAsync(EndPoint endPoint, CancellationToken cancellationToken)
 at MongoDB.Driver.Core.Connections.BinaryConnection.OpenHelperAsync(CancellationToken cancellationToken)

var servers = new List<MongoServerAddress>();

// Resolve hostnames
 foreach (var server in mongoDbSettings.Servers)
 {
    // hostname:port
    var parts = server.Split(':');

    var address = Dns.GetHostAddresses(parts[0])
        .FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork);

    servers.Add(new MongoServerAddress(address.ToString(), int.Parse(parts[1])));
 }

var mongoClientSettings = new MongoClientSettings
 {
    Servers = servers
 };