locationManager:rangingBeaconsDidFailForRegion:withError: kCLErrorDomain 16

Question

I have read CLLocationManager kCLErrorDomain Codes? as well as Apple Docs

I check to make sure ranging is available before calling startRangingBeaconsInRegion: and I am

Answer 1

Just to eliminate any possibility that it could be something in your code, try a reference app like my Locate for iBeacon. If it also does not work, you probably have an OS or hardware problem.

To troubleshoot this, first reboot your phone and try again. Then try pairing to a regular Bluetooth device (headphones, Mac, etc). If regular Bluetooth pairing works, it may be a Bluetooth LE issue.

Your iOS device must be either an iPhone 4s+ or an iPad 3+ (needed for BLE).