An attempt to connect to a host failed.
- iOS 2.0+
- macOS 10.2+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
This can occur when a host name resolves, but the host is down or may not be accepting connections on a certain port.
A connection was attempted while a phone call was active on a network that doesn’t support simultaneous phone and data communication, such as EDGE or GPRS.
A request for an FTP file resulted in the server responding that the file is not a plain file, but a directory.
The URL Loading System encountered an error that it can’t interpret.
A server reported that a URL has a non-zero content length, but terminated the network connection gracefully without sending any data.