# Troubleshooting

## Send a debug report

Call `sendDebugReport()` to collect and send device diagnostic logs to Finix. Use this when troubleshooting connectivity or transaction issues.

```kotlin
mpos.sendDebugReport()
```

## Firewall settings

The PAX D135 downloads its encryption keys from PAX servers during first-time configuration. This traffic uses the internet connection of the phone or tablet the D135 is paired with. If that network has a firewall, allow the following PAX hosts for the environment your Device is designated for:

| Environment | Host |
|  --- | --- |
| Sandbox | `rkilt.pax.us:33619` |
| Production | `rki.pax.us:33519` |


## 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.

## Version compatibility

SDK version 3.0.0 is a major update and is incompatible with earlier versions. If you have production devices running SDK version 2.0.0 or later, contact Finix before upgrading.

## Contact support

Email [support@finix.com](mailto:support@finix.com) with your debug report and a description of the issue.