SuiteQL HMAC-SHA256 signature

Hi. I'm working on c# SuiteQL rest application. Recently we've got error, that we need to change signature from HMAC-SHA1 to HMAC-SHA256.

Currently, we are using for creating signature Google api - OAuthBase.GenerateSignature. But, this method can't create HMAC-SHA256.

I've been looking through many different solutions, how to create signature manually, but all of them doesn't allow me to create request to NetSuite, i've got "InvalidSignature" error.

This is my current code:

//Creating signature and header
var signature = GenerateSignature(consumerKey,ConfigurationManager.AppSettings["login.tbaConsumerSecret"], ConfigurationManager.AppSettings["login.tbaTokenSecret"],nonce,time,                    tokenId, ConfigurationManager.AppSettings["login.acct"]).Replace("+", "%2B");

var header = $"Authorization: OAuth oauth_signature=\"{signature}\", oauth_version=\"1.0\", oauth_nonce=\"{nonce}\", oauth_signature_method=\"HMAC-SHA256\", oauth_consumer_key=\"{consumerKey}\", oauth_token=\"{tokenId}\",oauth_timestamp=\"{time}\", realm=\"{ConfigurationManager.AppSettings["login.acct"]}\"";
//Generating signature
private static string GenerateSignature(string consumerKey, string consumerSecret, string tokenSecret, string nonce, string timestamp, string token, string acct)
        {
            var baseString = $"{acct}&{consumerKey}&{token}&{nonce}&{timestamp}";
            var key = consumerSecret + "&" + tokenSecret;
            string signature;
            var encoding = new ASCIIEncoding();
            var keyBytes = encoding.GetBytes(key);
            var baseStringBytes = encoding.GetBytes(baseString);
            using (var hmacSha = new HMACSHA256(keyBytes))
            {
                var hashBaseString = hmacSha.ComputeHash(baseStringBytes);
                signature = Convert.ToBase64String(hashBaseString);
            }
            return signature;
        }