Popup camera pops up but no image is showing.

The popup camera of the phone does work as mechanically,because it does popup when ever selected front camera. But the issue is it does not generate any images or videos , and also hangs the devices. If we are taking it from the camera app , and when we choose the front cam ,it just pops up and shows a black screen. From then you cant get back to primary camera unless you go to settings>camera>clear cache. This is but when we take it with other thirdparty/video call applications it doesnt need to reset the camera app ,but results are same.