The video from my camera is black with SDK, while the official zoom works well

I am developing the desktop app based on win 10 with windows SDK. My computer hardware is a 2019 Mac book: i9-9880H CPU @2.3GHz, 16G mem, x64. The official zoom application works well. But my app with SDK shows back display for my own video. I checked the win 10 privacy for camera and it should be OK. I checked the camera with other apps, and all of them works well.
It worked well before yesterday. Actually I encountered such issue before and resolve it with reboot. But now it can not works. I use my another mac to check my binary, it works well. I test my Mac with windows on the go version on the same mac and it is the same issue.
I obsered that the official zoom app show the video from black to video for about 5~10 seconds.
Which version?
I test win 10 1903 and 1909(should be autaum version in 2019). I test win SDK demo and demo v2. They are same issue.

To Reproduce(If applicable)
Steps to reproduce the behavior:
1.Click the SDK demo, or click the SDK demo v2 with or without custom UI.
2. put the key/secret, login info in the appropriate place.
3. start or join a meeting
4. turn on the video.
5. the video for my camera is black.


Smartphone (please complete the following information):

Additional context

After I updated the SDK v4.4 with the new one V4.6. This problem is gone. Guess that it maybe relate to the server end Since it works before. I downloaded v4.4 about one week ago and the v4.6 was put on github 15 hours ago.
Anyway, the issue is gone. The ticket is closed.

Hi liuhuawei,

Thanks for using Zoom SDK and thanks for the update. Pardon the late response. Glad to hear that this issue has been resolved. Let me know if any other questions. Happy Zooming!