Some users has reported that they have problem discovering and connecting to the pin on their iPhones. This seems to be a common issue with the iPhone and Bluetooth devices as there are many guides online on how to "force" the iPhone to discover and pair with devices. This is a summary of those guides.
In some cases the pin might be paired with your device already. To make sure it isn't go to your Bluetooth settings, select the pin under "My devices" and "forget device".
Turn flightmode on and off
Turn flight mode on. Wait for a wile and then turn it off. Repeat this a couple of times. This will clear Bluetooth cache.
Turn bluetooth off and restart your phone
Turn bluetooth off. Restart your phone and turn bluetooth on. See if you can add the pin in the app.
Force restart your phone
This is different for different iPhone models. Find your model here and follow the instruction.
Reset Network Settings
You can try resetting your network settings. The downside of doing this is that it will reset all your Wi-Fi settings, which will force you to reconnect existing Wi-Fi networks after the procedure.
- Open Settings app and go to General > Reset
- Tap on Reset Network Settings
- Enter your passcode key if prompted, before you continue
- Confirm the action in the ensuing pop-up menu
Wait until your iOS device reboots and then try pairing the device via Bluetooth again.