C# JWT签名验证失败

我在验证JWT签名时遇到了一个非常奇怪的错误，在本地运行web应用程序时效果很好，但是在部署到服务器时，我收到了这个错误：

“消息：IDX10503:签名验证失败。尝试的密钥为：'System.IdentityModel.Tokens.InMemorySymetricSecurityKey\r\n'。\n捕获的异常：\n”“。\n标记：'{\'typ\'：\'JWT\'，\'alg\'：\'HS256\'。”

我像这样创建我的令牌

var securityKey = Encoding.UTF8.GetBytes(secret);

    var tokenHandler = new JwtSecurityTokenHandler();

    // Token Creation
    var now = DateTime.UtcNow;
    var tokenDescriptor = new SecurityTokenDescriptor
    {
        Subject = identity,
        TokenIssuerName = "self",                
        AppliesToAddress = "http://example.com",
        Lifetime = new Lifetime(now, now.AddMinutes(2)),
        SigningCredentials = new SigningCredentials(
     new InMemorySymmetricSecurityKey(securityKey),
     "http://www.w3.org/2001/04/xmldsig-more#hmac-sha256",
     "http://www.w3.org/2001/04/xmlenc#sha256"),
    };
    var token = tokenHandler.CreateToken(tokenDescriptor);

    return tokenHandler.WriteToken(token);

然后像这样验证：

        // Create token validation parameters for the signed JWT
        // This object will be used to verify the cryptographic signature of the received JWT
        TokenValidationParameters validationParams =
            new TokenValidationParameters()
            {
                ValidAudience = "http://example.com",
                ValidIssuer = "self",
                IssuerSigningToken = new BinarySecretSecurityToken(Encoding.UTF8.GetBytes(secret)),
            };

        var tokenHandler = new JwtSecurityTokenHandler();

        //   tokenHandler.ValidateToken(token, validationParams);

        SecurityToken st;
        principal = tokenHandler.ValidateToken(token, validationParams, out st);
        return true;

调用“token.ValidateToken（..）”时出错

有什么想法吗