Shopify Webhook Signature Verification in NetSuite

Question

I am trying to verify shopify webhook in NetSuite. But the SHA256 signature created in Suitescript doesn't match the Shopify signature. Here is the code used to generate the signature:-

var sKey = crypto.createSecretKey({
        guid: 'd4dba1012fd34132b161083039d0d5cd',
        encoding: encode.Encoding.UTF_8
                });
    var hmacSHA256 = crypto.createHmac({
        algorithm: crypto.HashAlg.SHA256,
        key: sKey
    });
    hmacSHA256.update({
         input: JSON.stringify(context.request.body),
         inputEncoding: encode.Encoding.UTF_8            
     });
    var digestSHA256 = hmacSHA256.digest({
        outputEncoding: encode.Encoding.BASE_64
    });
    
    log.debug('digestSHA256' , digestSHA256);

I guess I am doing as specified in the Shopify docs but the SHA256 doesn't match at all. Any ideas/help is much appreciated.