If your XY Find It appears as "searching" or "not detected" on your My Items screen for an indefinite period of time, that's usually due to either having a necessary settings disabled or due to a dead battery.
If you have Location and Bluetooth enabled, please try logging out of the XY app, restart Bluetooth and log back in to see if now there's a signal. If the issue persists, then it's probably the battery. XY Finders use replaceable CR2032 batteries. This video shows you how to open your XY Find It to replace the battery.