Hotfix/1354 working fh login

coscine/issues#1354

src/STS/Startup.cs

@@ -93,6 +93,8 @@ namespace Coscine.Api.STS
                     var x509Certificate2 = new X509Certificate2(pfx, passwordString);
 
                     options.SPOptions.ServiceCertificates.Add(x509Certificate2);
+
+                    options.SPOptions.WantAssertionsSigned = true;
                 });
         }
     }