We have some experience on it.
1.You need to test your band wide ,it must over 3000kbs, we are talking about upload speed.
2.if you upload speed enough, try to set the bitrate more ,just like 4000 or 5000.
3.if the upload bandwide is not more, Try to set the Resolution lower. like 1024768 or 800600.
4.Pay attention to the video source FPS. if the Video source FPS is 60, may be you need try set encoder to 40.
all the advice is option ,try each one at one time please.
Have a good day.