You might experience an issue where your Sony α 6x00 (a6100, a6300, a6400, a6500, a6600, or a7III) series DSLR randomly shuts off while being used as a camera in Ecamm Live. You may see a message on its view screen saying "Internal temp. high."
Try these steps to keep it from happening:
In the camera's on-screen menus, go to Setup, then find the Auto Power OFF Temp. menu.
Set this option to be High.
If you do not see this option on your Sony α series camera, try updating it to the latest firmware.
Here's some more info on this option: