---
title: NSURLErrorFailingURLErrorKey
framework: foundation
role: symbol
role_heading: Global Variable
path: foundation/nsurlerrorfailingurlerrorkey
---

# NSURLErrorFailingURLErrorKey

The URL which caused a load to fail.

## Declaration

```swift
let NSURLErrorFailingURLErrorKey: String
```

## Discussion

Discussion The corresponding value is an NSURL instance.

## See Also

### Keys

- [NSURLErrorFailingURLPeerTrustErrorKey](foundation/nsurlerrorfailingurlpeertrusterrorkey.md)
- [NSURLErrorFailingURLStringErrorKey](foundation/nsurlerrorfailingurlstringerrorkey.md)
- [NSURLErrorBackgroundTaskCancelledReasonKey](foundation/nsurlerrorbackgroundtaskcancelledreasonkey.md)
- [URL Session Background Task Cancellation Reasons](foundation/url-session-background-task-cancellation-reasons.md)
- [NSURLErrorNetworkUnavailableReasonKey](foundation/nsurlerrornetworkunavailablereasonkey.md)
- [URLError.NetworkUnavailableReason](foundation/urlerror/networkunavailablereason-swift.enum.md)