NSURLErrorTimedOut

NSURLErrorTimedOut is an error code in the NSURLErrorDomain used by Apple’s URL loading system to indicate that a network request did not complete within the allowed time. It signifies that a request or response failed to arrive before the specified timeout interval elapsed.

The code value for NSURLErrorTimedOut is -1001. When a timeout occurs, the error is delivered as an NSError in the completion handlers of URL loading operations, such as URLSession data tasks or NSURLConnection callbacks. The error’s domain is NSURLErrorDomain and the code is NSURLErrorTimedOut (-1001). The userInfo dictionary may include keys such as NSURLErrorFailingURLStringErrorKey and NSURLErrorFailingURLKey, along with a localized description of the issue.

Common causes include network connectivity problems, slow or unresponsive servers, large payloads, or overly aggressive timeout settings. Timeouts can also occur due to intermediate proxies or gateways that do not forward data promptly. Timeout behavior can be influenced by configuration: per-request timeouts can be set with URLRequest timeoutInterval, and session-wide timeouts can be configured with URLSessionConfiguration’s timeoutIntervalForRequest and timeoutIntervalForResource.

Handling NSURLErrorTimedOut typically involves retrying the request with backoff, possibly after verifying network availability. Developers may adjust timeout settings for long-running transfers, optimize request payloads, or provide user feedback and graceful failure handling. In some cases, separating large uploads or downloads into smaller chunks can reduce the likelihood of timeouts, and using background sessions may improve reliability on intermittent connections.

See also NSURLErrorDomain and NSURLErrorTimedOut.