LOTS of possibilities
real-time video encoding is VERY computationally demanding.
Primary issues are your PC being overloaded, and not being able to handle what you are asking it to do, or your network.
You are NOT using WiFi, right?
- What are you doing for monitoring hardware resource (CPU, GPU, RAM, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] to see if your system is being maxed out with your settings?
- then what you are doing to monitor your Internet connection? is anything else using that connection?