Ok If anyone suffers from the same problem, I am posting the solution I found. It seems other people also faced this problem and asked question here
It is a generic error for .Net Core 2.0 as far as i understand and it occurs if request lasts longer than 30 seconds.
As can be seen in upper link, they posted a solution here. It worked for me. Solution requires to make a fake request to service each time before making a real request so timeout settings can be changed. To avoid that I can suggest you to catch "CommunicationException", and apply the solution in that catch. So you make extra calls only if you really need to. I am copying the code, just in case link dies (all credits for code to https://github.com/mconnew/)
static void Main(string[] args)
{
var client = new SimpleServiceClient();
client.OpenAsync().GetAwaiter().GetResult();
client.DelayedResponseAsync(2000).GetAwaiter().GetResult();
var channel = client.InnerChannel;
var httpChannelFactory = client.InnerChannel.GetProperty<IChannelFactory>();
var cacheField = httpChannelFactory.GetType().GetField("_httpClientCache", BindingFlags.NonPublic | BindingFlags.Instance);
var httpClientCache = cacheField.GetValue(httpChannelFactory);
var cacheDictionaryField = httpClientCache.GetType().GetField("_items", BindingFlags.NonPublic | BindingFlags.Instance);
IDictionary cacheDictionary = (IDictionary)cacheDictionaryField.GetValue(httpClientCache);
foreach(var cacheKey in cacheDictionary.Keys)
{
var cacheEntry = cacheDictionary[cacheKey];
var valueField = cacheEntry.GetType().GetField("value", BindingFlags.NonPublic | BindingFlags.Instance);
HttpClient httpClient = (HttpClient)valueField.GetValue(cacheEntry);
FixHttpClient(httpClient);
}
client.DelayedResponseAsync(50000).GetAwaiter().GetResult();
Console.WriteLine("Done");
Console.ReadLine();
}
private static void FixHttpClient(HttpClient httpClient)
{
var handlerField = typeof(HttpMessageInvoker).GetField("_handler", BindingFlags.NonPublic | BindingFlags.Instance);
DelegatingHandler delegatingHandler = (DelegatingHandler)handlerField.GetValue(httpClient); // Should be of type ServiceModelHttpMessageHandler
WinHttpHandler winHttpHandler = (WinHttpHandler)delegatingHandler.InnerHandler;
WinHttpHandler newHandler = new WinHttpHandler();
newHandler.ServerCredentials = winHttpHandler.ServerCredentials;
newHandler.CookieUsePolicy = winHttpHandler.CookieUsePolicy;
newHandler.ClientCertificates.AddRange(winHttpHandler.ClientCertificates);
newHandler.ServerCertificateValidationCallback = winHttpHandler.ServerCertificateValidationCallback;
newHandler.Proxy = winHttpHandler.Proxy;
newHandler.AutomaticDecompression = winHttpHandler.AutomaticDecompression;
newHandler.PreAuthenticate = winHttpHandler.PreAuthenticate;
newHandler.CookieContainer = winHttpHandler.CookieContainer;
// Fix the timeouts
newHandler.ReceiveHeadersTimeout = Timeout.InfiniteTimeSpan;
newHandler.ReceiveDataTimeout = Timeout.InfiniteTimeSpan;
newHandler.SendTimeout = Timeout.InfiniteTimeSpan;
var servicemodelHttpHandlerInnerHandlerField = delegatingHandler.GetType().GetField("_innerHandler", BindingFlags.NonPublic | BindingFlags.Instance);
servicemodelHttpHandlerInnerHandlerField.SetValue(delegatingHandler, newHandler);
var delegatingHandlerInnerHandlerField = typeof(DelegatingHandler).GetField("_innerHandler", BindingFlags.NonPublic | BindingFlags.Instance);
delegatingHandlerInnerHandlerField.SetValue(delegatingHandler, newHandler);}