First of all there is a ton of question with the same title but I believe my problem is little bit different from other questions. I would like to state that everything where perfectly fine about two days ago. I haven’t changed anything in code.

We are not required to install any SSL certificate to our servers or local computers. The url of the WCF service opens normally on browser (https://sampleurl.com/service.svc)

I created a console application for testing purposes, it works but it doesn’t work on our .net mvc 5 project.

How I call service:

 CustomerServiceClient client = new CustomerServiceClient();
  client.ClientCredentials.UserName.UserName = "[email protected]";
  client.ClientCredentials.UserName.Password = "asfasf";

  var result = client.GetInformation("1MS0274796");

The response is;

System.ServiceModel.Security.SecurityNegotiationException: 'Could not establish secure channel for SSL/TLS with authority 'servis.vatanbilgisayar.com'.'
Inner Exception:
WebException: The request was aborted: Could not create SSL/TLS secure channel.

What I’ve tried

I added the line below before service call and it didn’t worked.

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

And

System.Net.ServicePointManager.ServerCertificateValidationCallback +=
    (se, cert, chain, sslerror) =>
        {
            return true;
        };

This addition to code throws error below;

The certificate key algorithm is not supported

web.config;

 <system.serviceModel>
        <bindings>
            <wsHttpBinding>
                <binding name="CustomerServiceSoap">
                    <security mode="TransportWithMessageCredential">
                        <transport clientCredentialType="None" />
                        <message clientCredentialType="UserName" />
                    </security>
                </binding>
            </wsHttpBinding>
        </bindings>
        <client>
            <endpoint address="https://xyzx.com/CustomerService.svc"
                binding="wsHttpBinding" bindingConfiguration="CustomerServiceSoap"
                contract="xfasf.asfasf" name="CustomerServiceSoap" />
        </client>
    </system.serviceModel>