@mross127 It’s possible that another device on the network is causing problems preventing the device from joining. The GE Link bulbs and previous generation of OSRAM/Sylvania and bulbs were especially known to cause problems with other devices. If you have any of those devices I would suggest powering them all off temporarily while you try to join the sensor. If you have any of the OSRAM/Sylvania bulbs it would also be a good idea to make sure they are on the latest firmware and updating them if they are not by following the instructions here: https://support.smartthings.com/hc/en-us/articles/215394303-Zigbee-OTA-firmware-updates.