---
title: AccessorySecuritySession.Error.unknown
framework: accessorytransportextension
role: symbol
role_heading: Case
path: accessorytransportextension/accessorysecuritysession/error/unknown
---

# AccessorySecuritySession.Error.unknown

Underlying failure with an unknown cause.

## Declaration

```swift
case unknown
```

## See Also

### Interpreting the error cause

- [AccessorySecuritySession.Error.invalidated](accessorytransportextension/accessorysecuritysession/error/invalidated.md)
- [AccessorySecuritySession.Error.unsupported](accessorytransportextension/accessorysecuritysession/error/unsupported.md)