Siteflow API - Base URL question, and also getting a 500 server error - are docs up to date?

Hello,

I cloned the GitHub repo and I'm trying to get a simple GetProducts() call working.

1. I have a key and secret provided by one of our HP contacts, but I'd like to generate a key if possible.  Does that option exist, or does HP have to provide them?

2. Is the base URL supposed to be https://printos.api.hp.com/siteflow? The example in the repo is for box and it uses that, but with /box, so I assume it's correct.

3. Here is the call I am making, but it's coming back with an Internal Server Error 500 error. Any ideas? I got the /api/product for the header from the dev API documentation website.

Here's the code - but I noticed the Git repo is 4 years old, so it may be really outdated by now.

private static async Task GetProducts()

        {
            Console.WriteLine("Getting list of products");
            using (var client = new HttpClient())
            {
                CreateHmacHeaders("GET", "/api/product", client);

                HttpResponseMessage response = await client.GetAsync(baseUrl_Siteflow + "/api/product");

                if (response.IsSuccessStatusCode)
                {
                    Console.WriteLine("Success. Products found.");
                    string info = await response.Content.ReadAsStringAsync();
                    Console.WriteLine(info);
                }
                else
                {
                    Console.WriteLine("Failure. Unable to get list of Products.");
                    Console.WriteLine(response.ReasonPhrase);
                }
            }
        }