The HMAC string Iktz/AdXHmDouNm6uBB8ZW0xcfNGuWGDxmX9TFMwuF0=
refers to the request in v1 API instead of v2. Kindly you could update the example HMAC-SHA256 value.
https://docs-developers.refinitiv.com/1600949101673/50009/documentation/schema-reference/security.html#_http_request_example