为什么我的STS客户端出现此错误？"无法解析'type'属性的值.验证'issuerNameRegistry的type属性..."

我经常遇到这个错误,我的努力没有任何结果.错误:

ID8030:无法解析'type'属性的值.验证'issuerNameRegistry type ="Webapp1.TrustedIssuerNameRegistry,webapp1"元素的type属性是否正确.

这是我的TrustedIssuerNameRegistry类:

    namespace Webapp1
{
    public class TrustedIssuerNameRegistery : IssuerNameRegistry
    {
        private string issuerName = string.Empty;

        public override string GetIssuerName(SecurityToken securityToken)
        {
            if (securityToken != null)
            {
                X509SecurityToken x509Cert = securityToken as X509SecurityToken;
                if (x509Cert != null && x509Cert.Certificate.SubjectName.Name == "CN=busta-ip1sts.com")
                {
                    issuerName = x509Cert.Certificate.SubjectName.Name;
                }
            }
            if (string.IsNullOrEmpty(issuerName))
            {
                throw new SecurityTokenException("Untrusted issuer.");
            }

            return issuerName;
        }

        public override string GetIssuerName(System.IdentityModel.Tokens.SecurityToken securityToken,
                                             string requestedIssuerName)
        {
            return base.GetIssuerName(securityToken, requestedIssuerName);
        }
    }
}

这是我的web.config配置: