NetMQ Request/Response sometimes fails when reopen the response server

Question

I am trying to use NetMQ to send and receive messages from the Request/Response pattern. I want to simulate network disconnect by reopen the response server. The messaging sometimes fails when reopen the response server.

What am I doing wrong? Any information or assistance would be greatly appreciated.

Request Client:

RequestSocket client = new RequestSocket();
client.Connect(address);
while(true)
{
    client.SendFrame(dataBytes);
    client.ReceiveFrameString();
    Thread.Sleep(100);
}

Also tried Request Client with Try*, and re-connect if the client does not receive any reponse for a while:

bool success = false;
while(true)
{
    success = client.TrySendFrame(TimeSpan.FromMilliseconds(500), dataBytes);
    if (success)
    {
        break;
    }
    Thread.Sleep(100);
}

int count = 0;
success = false;
while(true)
{
    success = client.TryReceiveFrameString(TimeSpan.FromMilliseconds(500), out string s);
    if (success)
    {
        break;
    }
    count++;
    if (count >= 50)
    {
        client.Disconnect(address);
        client.Connect(address);
        break;
    }
    Thread.Sleep(100);
}

Response Server (manually close and open program again):

ResponseSocket server = new ResponseSocket(connection);
while(true)
{
    if (server.TryReceiveFrameBytes(TimeSpan.FromMilliseconds(300), out byte[] dataBytes))
    {
        server.SendFrame("Response");
    }
    Thread.Sleep(100);
}