# Troubleshooting

## Bluetooth permission

If scanning returns no devices, verify that your app has been granted Bluetooth access. When running for the first time, the OS shows a permission prompt during the first `startScan()` call. If the user dismisses the scanner before tapping Allow, have them dismiss and re-open the scanner after granting permission in Settings.

The `NSBluetoothAlwaysUsageDescription` key must be present in your `Info.plist` before the prompt will appear.

## Physical device required

The SDK cannot run on the iOS Simulator. Deploy to a physical device for all testing with the PAX D135.

## Device pairing indicators

| LED | Status |
|  --- | --- |
| Orange | Ready for pairing |
| Green | Battery fully charged |
| Green only (post-connect) | Connected and ready |
| Blue | Waiting for card interaction |
| Off + beeping | Card detected |


## Troubleshooting Your Terminal

For device-level issues such as connectivity, charging, and LED status, see the [Troubleshooting Your Terminal](/guides/in-person-payments/troubleshooting-your-terminal) guide.

## Contact support

Email [support@finix.com](mailto:support@finix.com) with a description of the issue, your device serial number, and your SDK version.