Get 401 when calling Check-CaseId-Availability in C#

Hi,

So far I am able to make other calls through C#.

When I try to check for my case id availability, I keep getting 401 but it works in Postman

Can you please review if I make any mistake with the call data?

requestendpoint = "https://api-worldcheck.refinitiv.com/v2/caseIdentifiers?caseId=BENNINGTON_1"

dataToSign = "

(request-target): head /v2/caseIdentifiers?caseId=BENNINGTON_1

host: api-worldcheck.refinitiv.com

date: Tue, 27 Jul 2021 22:04:10 GMT

"

authorization = "Signature keyId="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",algorithm="hmac-sha256",headers="(request-target) host date",signature="5UB8TMDsCRIO0FIc3Jc7j9QLgLYWehGWc3PiE3keb+w=""

WebReq.Method = "HEAD";

WebReq.Headers.Add("Authorization", authorisation);

WebReq.Headers.Add("Cache-Control", "no-cache");

WebReq.Date = dateValue; // use datetime value GMT time

Thank you,

Cady