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# URLError.NetworkUnavailableReason

An enumeration of reasons explaining why a task couldn’t satisfy networking constraints.

```
enum NetworkUnavailableReason
```

## Overview

The network may be unavailable due to restrictions placed on the [`URLSessionConfiguration`](/documentation/Foundation/URLSessionConfiguration), such as [`allowsConstrainedNetworkAccess`](/documentation/Foundation/URLSessionConfiguration/allowsConstrainedNetworkAccess), [`allowsExpensiveNetworkAccess`](/documentation/Foundation/URLSessionConfiguration/allowsExpensiveNetworkAccess) and [`allowsCellularAccess`](/documentation/Foundation/URLSessionConfiguration/allowsCellularAccess).

## Topics

### Unavailability reasons

[`case cellular`](/documentation/Foundation/URLError/NetworkUnavailableReason-swift.enum/cellular)

A reason that indicates network is unavailable because the interface is cellular and cellular network is disabled.

[`case constrained`](/documentation/Foundation/URLError/NetworkUnavailableReason-swift.enum/constrained)

A reason that indicates network is unavailable because the user enabled “Low Data Mode” in the Settings app.

[`case expensive`](/documentation/Foundation/URLError/NetworkUnavailableReason-swift.enum/expensive)

A reason that indicates network is unavailable because the system marked the interface as expensive.

### Enumeration Cases

[`case ultraConstrained`](/documentation/Foundation/URLError/NetworkUnavailableReason-swift.enum/ultraConstrained)

## Relationships

### Conforms To

[`Equatable`](/documentation/Swift/Equatable)

[`Escapable`](/documentation/Swift/Escapable)

[`Sendable`](/documentation/Swift/Sendable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Copyable`](/documentation/Swift/Copyable)

[`Hashable`](/documentation/Swift/Hashable)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

---

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