Why does the error message "T3 timeout" occur after running for a period of time, but it resumes after restarting the service? All time settings are 5000ms. My service is in passive mode

[BL699]

Why does the error message "T3 timeout" occur after running for a period of time, but it resumes after restarting the service? All time settings are 5000ms. My service is in passive mode and my connection status is still Selected
Here is my connecttion settings

            var options = Options.Create(new SecsGemOptions
            {
                IsActive = _gemOptionDto.IsActive,
                IpAddress = _gemOptionDto.IpAddress,
                Port = _gemOptionDto.Port,
                SocketReceiveBufferSize = _gemOptionDto.SocketReceiveBufferSize,
                DeviceId = _gemOptionDto.DeviceId,
                LinkTestInterval = 10000,
                T3 = _gemOptionDto.T3,
                T5 = _gemOptionDto.T5,
                T6 = _gemOptionDto.T6,
                T7 = _gemOptionDto.T7,
                T8 = _gemOptionDto.T8,
                EncodeBufferInitialSize = _gemOptionDto.EncodeBufferInitialSize,
            });

            SecsGem?.Dispose();

            if (_connector != null)
            {
                await _connector.DisposeAsync();
            }

            _connector = new HsmsConnection(options, _logger);
            SecsGem = new SecsGem(options, _connector, _logger);
            _connector.ConnectionChanged += OnConnectionChanged;
            _connector.LinkTestEnabled = true;
            _connector.Start(_cancellationTokenSource.Token);

[gzfred]

The T3 timeout is meaning your program have send a message to target and expect the target will reply, but after 5000ms, the target still not reply, so the T3 timeout occur. You should check that why the target not reply to you.