I'm building an app that makes a http POST call to my own backend, hosted on google cloud platform. The app crashes randomly, due to NSURLErrorDomain Code=-1017 Task <718E46A2-8F9E-45C2-A324-38320C24E4D1>.<4> HTTP load failed, 1063/0 bytes (error code: -1017 [4:-1]) Task <718E46A2-8F9E-45C2-A324-38320C24E4D1>.<4> finished with error [-1017] Error Domain=NSURLErrorDomain Code=-1017 "nie można zanalizować odpowiedzi" UserInfo={_kCFStreamErrorCodeKey=-1, NSUnderlyingError=0x2823a2d60 {Error Domain=kCFErrorDomainCFNetwork Code=-1017 "(null)" UserInfo={_kCFStreamErrorCodeKey=-1, _kCFStreamErrorDomainKey=4}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <718E46A2-8F9E-45C2-A324-38320C24E4D1>.<4>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <718E46A2-8F9E-45C2-A324-38320C24E4D1>.<4>" ), NSLocalizedDescription=nie można zanalizować odpowiedzi, NSErrorFailingURLStringKey=https://api.dev.<backend>.co/payment/bm/pay, NSErrorFailingURLKey=https://api.dev.<backend>.co/payment/bm/pay, _kCFStreamErrorDomainKey=4} Runner/NewsViewController.swift:213: Fatal error: unexpected response Runner/NewsViewController.swift:213: Fatal error: unexpected response * thread #47, queue = 'com.apple.NSURLSession-delegate', stop reason = Fatal error: unexpected response frame #0: 0x00000001acaca458 libswiftCore.dylib`_swift_runtime_on_report libswiftCore.dylib`: -> 0x1acaca458 <+0>: ret libswiftCore.dylib`: 0x1acaca45c <+0>: b 0x1acaca458 ; _swift_runtime_on_report libswiftCore.dylib`: 0x1acaca460 <+0>: adrp x8, 334844 0x1acaca464 <+4>: ldrb w0, [x8, #0x65c] Target 0: (Runner) stopped. This happens absolutely randomly. I've seen a couple of issues here on the apple forum, but none of them clearly describes what is the reason behind this error. The request is simply built as follows:     request.httpMethod = "POST" //set http method as POST     request.allowsCellularAccess = true;     request.allowsExpensiveNetworkAccess = true;     request.allowsConstrainedNetworkAccess = true;     do {       request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: .prettyPrinted) // pass dictionary to nsdata     } catch let error {       Amplitude.instance().logEvent("Error serializing POST parameters", withEventProperties: parameters)     }     request.addValue("application/json", forHTTPHeaderField: "Content-Type")     request.addValue("application/json", forHTTPHeaderField: "Accept")     request.addValue(appDelegate.variables!["X-UserPermission"] as! String, forHTTPHeaderField: "X-UserPermission")     request.addValue(appDelegate.variables!["Authorization"] as! String, forHTTPHeaderField: "Authorization")     request.httpShouldUsePipelining = true;