Using Zephyr Enterprise API to fetch details.

Hi,

I have created a test account for Zephyr Enterprise "https://testaccountAPI.zephyrdemo.com/flex/html5/release/1".

I had created an API token and was trying to fetch the details busing the below code snippet , but the same fails.Can you please guide me what I am doing wrong here or can you please guide me to the documentation for the same? I have gone through the steps mentioned at "https://zephyr67.docs.apiary.io/#reference/releases/get-release-by-release-id", but here it doesn't tell us about API token and details. 

Response response = client.target("https://testaccountAPI.zephyrdemo.com/flex/services/rest/latest/release/1")
        .request(MediaType.TEXT_PLAIN_TYPE)
        .header("Authorization", "***********************************************************")
        .get();