So far I’ve added about 10 Ecolink Door/Window sensors. All but one with no issues.
For some reason, this one sensor will not enter inclusion mode. I’ve done as the manual directs with no success. I also tried excluding it with no success.
I’ve left the battery out of the sensor for a few hours, set my SmartTihngs Hub to inclusion mode, insert the battery and replace the cover. The red LED will flash for a few seconds and then turn off.