Ring Battery Doorbell Plus is offline or unavailable

The checks in more detail

the pack is removable, and you can charge it with the USB cable while it sits in the doorbell or off it, and a spare battery gives you a doorbell that never goes dark. If the battery is fine, look at the signal. The doorbell sits at the front door, often far from the router and behind a wall, so Device Health may show a poor reading, and the fix is to move the router, add an extender or use a Ring Chime Pro, which Ring sells to extend the range of Ring devices.

Next do a power cycle, which Ring describes for battery devices as removing the battery pack for ten seconds and putting it back. Restart the router, and give it a few minutes. Ring says its doorbells need the 2.4 GHz band or a 5 GHz network where supported, and that the network name and password must match what the doorbell was set up with; if you changed the router or the password, the doorbell needs to be set up again on the new details, which is done with a reset and the app's Reconnect to Wi-Fi option.

Check that the router is not set to block unknown devices and that the doorbell's address is not changed by a mesh system. A doorbell that goes offline at the same time each night may be affected by a router that restarts then. If these steps fail, reset the doorbell by holding the setup button for 20 seconds, which on a removable battery model sits under the faceplate on the front, then set it up again. If it still will not connect, contact Ring support with the Device Health details.