---
title: NEURLFilterManager.Error.unknown
framework: networkextension
role: symbol
role_heading: Case
path: networkextension/neurlfiltermanager/error/unknown
---

# NEURLFilterManager.Error.unknown

The system encountered an unknown error.

## Declaration

```swift
case unknown
```

## See Also

### Other errors

- [NEURLFilterManager.Error.internalError](networkextension/neurlfiltermanager/error/internalerror.md)