I'm not thoroughly familiar with that cam, but most cams have a "hard reset" function- usually a tiny hole with the letter "R" next to it. Use a straightened paperclip and you'll feel a switch inside that hole. Press and hold the switch for 5 seconds, remove paper clip, then try the cam. This usually resolves the symptoms you're having. Also could be an app problem, so uninstall the app and reload a fresh version.
Phil