用户在调起支付时，会出现防诈骗的提示？请问为什么？如何去除

jsapi支付接口回调验签结果总是false 是什么原因呢 //certPublickey 解密后平台证书的公钥 // sign 接口应答签名 //s 接口应答字符串（应答时间戳\n应答随机串\n应答主体\n）   public bool VerifySign(string certPublickey, string sign, string s)     {         writeLog(certPublickey+",,"+sign+",,"+s);         X509Certificate2 publicCert = new X509Certificate2(Encoding.UTF8.GetBytes(certPublickey));         RSACryptoServiceProvider publicKey = (RSACryptoServiceProvider)publicCert.PublicKey.Key;         SHA256CryptoServiceProvider sHA = new SHA256CryptoServiceProvider();         return publicKey.VerifyData(Encoding.UTF8.GetBytes(s), sHA, Convert.FromBase64String(sign));     }