I have enabled geolocation and there are no wi-fi devices in the vicinity, but the pulse oximetry is not recognised

The cache memory of your Bluetooth device could be full and need clearing. In your phone’s settings, under applications, find the option for managing Bluetooth to be able to access it and clear the cache memory. To be able to see it, you need to enable system apps from the settings-applications menu. For further details, consult the manufacturer of your mobile.