---
title: NSURLErrorBackgroundTaskCancelledReasonKey
framework: foundation
role: symbol
role_heading: Global Variable
path: foundation/nsurlerrorbackgroundtaskcancelledreasonkey
---

# NSURLErrorBackgroundTaskCancelledReasonKey

A key in the error dictionary that provides the reason for canceling a background task.

## Declaration

```swift
let NSURLErrorBackgroundTaskCancelledReasonKey: String
```

## Discussion

Discussion The value associated with this key is an NSNumber. For a list of possible values, see URL Session Background Task Cancellation Reasons.

## See Also

### Keys

- [NSURLErrorFailingURLErrorKey](foundation/nsurlerrorfailingurlerrorkey.md)
- [NSURLErrorFailingURLPeerTrustErrorKey](foundation/nsurlerrorfailingurlpeertrusterrorkey.md)
- [NSURLErrorFailingURLStringErrorKey](foundation/nsurlerrorfailingurlstringerrorkey.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)