Having trouble pairing your iPhone with your new Bluetooth device? Clock radios, wireless speakers, headsets, and several other devices made by iHome, Philips, Ion, Logitech and Sony may have trouble pairing the Bluetooth with your iPhone, but it's not necessarily the Bluetooth device's fault. The cause is probably on your iPhone.
iPhones have a number of default network settings turned on that often interfere with Bluetooth pairing. So if your phone is giving you're the dreaded Pairing Unsuccessful error message, here's a couple things to try. These tricks have worked for me more than once.
First, turn off wi-fi in the Settings. Then in Cellular Network settings, turn off cellular data, turn off LTE and basically anything in there. Also, remember what all you change, so you can change it back later. After turning off those settings, double tap the home button so you can shut down individual apps. Swipe until the settings app is in the middle then swipe up on that app to shut that app down. Once you've turned all that off, turn the whole phone off. Hold down the top button for several seconds and wait for the prompt to turn the phone completely off. Wait a few seconds then turn the phone back on. Now try and pair the Bluetooth. Once you have the successful pairing, you can turn the rest of those settings back to where they were originally.