World check one API - 401 unauthorized when testing connection from SOAP or Fiddler

This is the first time we are working on World check API. We are testing authorization and connection process. We already have secret key and API key. Below request we are using to generate hash value from secret key.

(request-target): post /v1/cases
host: rms-world-check-one-api.thomsonreuters.com
date: Fri, 28 Sep 2018 09:29:59 GMT
content-type: application/json
content-length: 88
{
"caseId": "my customer ID",
"name": "John Doe",
"providerTypes": ["WATCHLIST"]
}

After generating Hash value we are sending request from SOAP-ui. Below is the request as checked in fiddler which is sent to World check API when sent from SOAP-UI.

POST https://rms-world-check-one-api-pilot.thomsonreuters.com/v1/cases HTTP/1.1 Date: Fri, 28 Sep 2018 09:29:59 GMT
Authorization: Signature keyId="xxxxxxxxxxxxxxxxxxxxxxxxx",algorithm="hmac-sha256", headers="(request-target) host date content-type content-length", signature="2qvdOiSvDZCogwO1VY+V3F1NdTmkqrhO/rUW2CJ16nM="
Content-Type: application/json
Content-Length: 88
Host: rms-world-check-one-api-pilot.thomsonreuters.com
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)
{
"caseId": "my customer ID",
"name": "John Doe",
"providerTypes": ["WATCHLIST"]
}

Below is the response we are getting -

HTTP/1.1 401 Unauthorized
X-Application-Context: application
Authorization: WWW-Authenticate: Signature realm="World-Check One API",algorithm="hmac-sha256",headers="(request-target) host date content-type content-length
Transfer-Encoding: chunked
Date: Fri, 28 Sep 2018 09:30:15 GMT
Server: ""

Please help on this.