Video Doorbell Keeps Freezing

I have a Video doorbell that keeps freezing every 2 hours. As it is battery powered, I have to remove the doorbell, plug it into the charger and eventually it reconnects and all is good. Approx 2 hours later it will stop working and I have to plug it back in to the charger again. I have charged the doorbell for over 12 hours and I have tried moving the doorbell next to my WIFI router, then leaving it but again a couple of hours later it has frozen and I have to plug back into the charger to get it working again. I have tried a factory reset, including deleting the device from the app but the problem persists. Occasionally it will go through a cycle of rebooting as the blue LED's flash for a couple few seconds and then it will reconnect. Any suggestions on how to resolve?