ASP.NET MVC To Signe as per ITIDA Egypt standards for Egypt eInvoicing using SignerDigital.signHashCAdESEg

Question

I'm working on asp.net MVC Project to sign and send e-invoice as per ITIDA Egypt standards for Egypt E-Invoicing I used Signer.Digital Browser Extension provided from Signer.Digital
as per Sign hash using CADES-BES signature using USB token My problem is when I sign an invoice become invalid like this enter image description here

Note: My steps to sign the data 1- I prepare the invoice json

2- I creating a canonical string from json an i got somthing like that https://sdk.preprod.invoicing.eta.gov.eg/files/one-doc-serialized.json.txt

3- hashing the serialized string by (what I think the propelm is )

byte[] result = Encoding.UTF8.GetBytes(canonicalString);

this code is not working for me then I tried

 var result = GetHash(canonicalString, System.Text.Encoding.UTF8);

 public static string GetHash(string value, System.Text.Encoding encoding)
    {
        string result = string.Empty;

        using (SHA256 mySHA256 = SHA256.Create())
        {
            byte[] valueArr = null;

            if (encoding == System.Text.Encoding.ASCII)
                valueArr = System.Text.Encoding.ASCII.GetBytes(value); //convert string value to byte[]
            else if (encoding == System.Text.Encoding.Default)
                valueArr = System.Text.Encoding.Default.GetBytes(value); //convert string value to byte[]
            else if (encoding == System.Text.Encoding.UTF7)
                valueArr = System.Text.Encoding.UTF7.GetBytes(value); //convert string value to byte[]
            else if (encoding == System.Text.Encoding.UTF8)
                valueArr = System.Text.Encoding.UTF8.GetBytes(value); //convert string value to byte[]
            else if (encoding == System.Text.Encoding.UTF32)
                valueArr = System.Text.Encoding.UTF32.GetBytes(value); //convert string value to byte[]
            else
                throw new Exception("Encoding not supported");

            using (MemoryStream ms = new MemoryStream(valueArr))
            {
                //compute hash
                byte[] hashValue = mySHA256.ComputeHash(ms);

                //for testing, output hash value as HEX

                System.Diagnostics.Debug.WriteLine("hashValue.Length: " + hashValue.Length + " bytes");

                for (int i = 0; i < hashValue.Length; i++)
                {
                    System.Diagnostics.Debug.Write($"{hashValue[i]:X2}");

                    if ((i % 4) == 3)
                        System.Diagnostics.Debug.Write(" ");
                }

                //convert to Base64 string
                result = Convert.ToBase64String(hashValue);

                //convert to string
                //result = System.Text.Encoding.UTF8.GetString(hashValue);

                System.Diagnostics.Debug.WriteLine("result: " + result);
            }
        }

        return result;
    }

4- then I Pass the result to javascript

SignResult = await SignerDigital.signHashCAdESEg(result);

5- prepare full Document Json by adding signature result to Json and "{"documents":[" things then posting the invoice.