Unable to add First Alert Smoke/CO2 2nd Gen

Hi all,
I’ve tried all the trick I found in the existing threads, including removing the device from the base as suggested here (which, alas, doesn’t seem to go through) but it keeps telling me to open the battery tray and close it.

Any thoughts on what I may be doing wrong?

Hi @salvino. The First Alert Smoke/CO2 sensor is not compatible with the UK Ring Alarm system.