TLS1.2启用服务器的证书固定问题

Question

虽然我使用以下代码在iOS和Android中固定证书，但我的回调被调用并且固定已完成，但是当使用TLS1.2更新服务器时，我们的回调被调用iOS，但它没有在Android中调用

void PinServerCertificate()
    {
        try
        {
            ServicePointManager.ServerCertificateValidationCallback += ServicePointManager_ServerCertificateValidationCallback;
            WebRequest wr = WebRequest.Create(GlobalVariables.BaseURL);
            wr.GetResponse();
        }
        catch (Exception ex)
        {
            RemoLogger.Log("Exception" + ex.Message);
        }
    }
bool ServicePointManager_ServerCertificateValidationCallback(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certificate, System.Security.Cryptography.X509Certificates.X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
    {
        if (null == certificate)
        {
            CertificateValidation.IsValid = false;
            return false;
        }
        string pk = certificate.GetPublicKeyString();
        if (pk.Equals(this.publicKey))
        {
            CertificateValidation.IsValid = true;
            return true;
        }
        CertificateValidation.IsValid = false;
        return false;
    }

Followed below link for TLS1.2 support

我们使用AndroidClientHandler和Managed [HttpClientHandler]进行了检查，但没有得到任何解决方案，请告知我们在Android中出了什么问题。

感谢您的帮助