If the other device is a watch, there are issues with the find app and watches that began with OneUI7. If you try tapping the find app on the watch, it will tell you the watch has not finished registering you to your account. I have reported it several times, and you should put in an error report, as well, currently there is no fix for it, although support did suggest disconnecting the watch and uninstalling and reinstalling the Wear app. I decided to use Google Find Hub instead.
