Ggtcf

I know that there is a lot of information about this error on StackOverflow and other resources, but it's working perfectly on my dev machine and now working on the customer environment Windows Server 2012. Here is my code.

public sealed class Certificates

 private static bool subscribed = false;

 private static Certificates instance = null;

 private static readonly object padlock = new object();

 private Certificates() 

 public static Certificates Instance
 
 get
 
 lock (padlock)
 
 if (instance == null)
 instance = new Certificates();
 return instance;
 
 
 

 public void GetCertificatesAutomatically()
 
 if (!subscribed)
 
 SecurityProtocolType.Tls 
 

 private static bool RemoteCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
 
 // Return true if the server certificate is ok
 if (sslPolicyErrors == SslPolicyErrors.None)
 return true;

 bool acceptCertificate = true;
 StringBuilder msg = new StringBuilder("The server could not be validate for the following reason():");

 // The server did not present a certificate
 if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateNotAvailable) == SslPolicyErrors.RemoteCertificateNotAvailable)
 
 msg.AppendLine(" - The server did not present a certificate.");
 acceptCertificate = false;
 
 else
 
 // The certificate does not math the server name
 if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateNameMismatch) == SslPolicyErrors.RemoteCertificateNameMismatch)
 
 msg.AppendLine(" - The certificate name does not match the authenticated name.");
 acceptCertificate = false;
 

 // There is som other problem with certificate
 if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateChainErrors) == SslPolicyErrors.RemoteCertificateChainErrors)
 
 foreach (X509ChainStatus item in chain.ChainStatus)
 
 if (item.Status != X509ChainStatusFlags.RevocationStatusUnknown &&
 item.Status != X509ChainStatusFlags.OfflineRevocation)
 
 SLICLog.Error($" - item.StatusInformation.");
 break;
 
 if (item.Status != X509ChainStatusFlags.NoError)
 
 msg.AppendLine($" - item.StatusInformation.");
 acceptCertificate = false;
 
 
 
 

 // if validation failed, write log
 if (!acceptCertificate)
 
 acceptCertificate = true;
 

 return acceptCertificate;
 

then I used the next code

 Host = new Uri(credential.Domain);

 if (Host.Scheme.Contains("https"))
 Certificates.Instance.GetCertificatesAutomatically();
using (HttpWebResponse httpWebResponse = httpRequest.GetResponse() as HttpWebResponse)
 using (var response = httpWebResponse.GetResponseStream())
 using (var sr = new StreamReader(response))
 
 token = JsonConvert.DeserializeObject<SessionInternal>(sr.ReadToEnd());
 if (token != null)
 
 Authorized = true;
 token.Exprired = DateTime.Now.AddSeconds(Convert.ToDouble(token.expires_in));
 
 

The problem is that ServerCertificateValidationCallback being ignored on the environment machine (I know it from log that I have added just for debugging).

On the one website, I read that Microsoft does not allow this to ignore self-signed certificates on Server machines, but not sure. The same code works on Windows10 and does not work on Windows Server 2012 and also settings for API server the same too, I mean the host url and credentials are identical.
.NET Framework 4.7.2

UPDATED:

I don't know why, but another server with a self-signed certificate works, I mean I run the code on the environment server to work with another API server (it's another kind of API) and ServerCertificateValidationCallback delegate is called. I have tried to research network via Wireshark and that is a part of a bad connection between client/server
And this is a normal connection with another server
I'm confused but same code and only different IP of API servers and different behavior