Why Ubuntu 20.04 doesn't run Droidcam?

I tried to install Droidcam in my computer, but the same error message is poping up always when I run the app "droidcam video device not found (/dev/video[0-9]). I also tried to uninstall but for some reason idk "permission denied" shows in my terminal. Please, someone help me, my remote classes back tomorrow and I need decent webcam to work.