Euyfycam 2 goes offline after a few seconds

Today I was looking in the eufysecurity app, and I could not find my eufycam 2. It dissapeared in the the app. The doorbell was stil online.
The battery is full, so I tried to reconnect, but within a minute, it dissapeared again. It gave some beeps, and then offline.

How can this be fixed?

coukd be low battery ?