Cannot reestablish communication with serial device in c#

Question

As title says I can not reestablish connection with a serial device without detach / attach the usb cable.

This is how it works in pseudo code :

public class SerialCommunicaiton
{
    proteced SerialPort serial_port = null
    protected string serial_port_name;
    
    [...]


    public SerialCommunication(string _serial_port_name)
    {
        serial_port_name = _serial_port_name;
    }


    public virtual bool Open(bool dtr = true)
    {
        try
        {
            if ((serial_port == null || !serial_port.IsOpen))
            {
                serial_port = new SerialPort(serial_port_name)
                {
                    BaudRate = 115200,
                    DataBits = 8,
                    StopBits = StopBits.One,
                    DtrEnable = dtr, 
                
                };
            serial_port.Open();
        }
        
        catch()[...]
    }
      
}


public SubClass : SerialCommunication
{
    [...]
    
    public override bool Open()
    {
        bool isOK = base.Open(false); 

        if(isOK)
        {
             serial_port.DataReceived += Serial_port_DataReceived;
 
             return Init();
        } 
        
        [...]      
    }

    [...]
}

In the Init() method i simply send some data to the device. The device should always reply with \u002ACK\x0d or \u002NACK\x0d even to unknown commands.

First connection works like a charm, but when program crashes or I close it I cannot reconnect to the device through the override bool Open() method because I do not receive any response from the device. I can send whatever I want through the serial port but I do not receive any data, synchronous or asynchronous mode changes nothing.

The fun thing, however, is that the only way to reestablish connection is to unplug/plug the device or to use a simply python program or a 3rd part software and sending some data to the device which actually replies with the expected strings. After that the overmentioned code works again.

I tried to check the SerialPort serial_port object in both working and not working status but it has the same exact properties so my best guess is there are some problems at lower level but I can not find what could it possibly be.