Ring Peephole Cam Device Offline

Hello, I started to use my peephole for around 3 months, but suddenly the device becomes offline, already checked the flat cable connection and charged the battery. the status of the light means that the device is booting up (Blue circle is flashing, one second on, one second off). I tried to reset the device to install again (press the orange button for 20 seconds) but the device don't enter on "setup mode". and tried to reboot my router as the app recommends, does anyone already had the same problem? thank you!