EufyCam Disappearing

One of my EufyCams (T8114P0219430560) disappeared from device list. I brought it in, recharged it and added to devices again. Worked about three days and disappeared again. Now cannot re-add to device and gets error 204. It now beeps once, then twice every minute or so, although not connected to Homebase. It has been banished to outbuilding until fixed or battery dies. Any ideas?