After installation the doorbell works - but after 2 min it's offline and white ring circles

Hi, My newly installed Video Doorbell Pro connects to the wifi router with strong signal. Everything works and it shoots video. Even the IR LEDs are working. But then after a pair of minutes the IR LEDs go Off and then the previously white dimmed circle lits up and starts circling. And in the app it says it's not reachable anymore. I have rebooted and reinstalled (in the app) the Doorbell but the same issues shows up over and over... Firmware is up to date the app says.What can be wrong?BrStefan