Basic Auth not working when trying to get raw contents from BitBucket?

I'm trying to download file contents from Bit Bucket, but I keep getting a "Log In" page as a response. I'm providing credentials with Basic Auth. Is this a C# specific issue? Everything works fine if I try it via Postman. Code Below.

        var url = "https://[BITBUCKET_DOMAIN]/projects/[ID]/repos/[REPO]/raw/[PATH_TO_MY_FILE]"

        var uri = new Uri(url);
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
        string userName = Environment.GetEnvironmentVariable("BitBucketUserName", EnvironmentVariableTarget.User);
        string password = Environment.GetEnvironmentVariable("BitBucketPassword", EnvironmentVariableTarget.User);
        request.PreAuthenticate = true;
        request.Credentials = new NetworkCredential(userName, password);
        request.Accept = "text/plain";

        string result;

        using (var response = request.GetResponse())
        using (var stream = response.GetResponseStream())
        using (var reader = new StreamReader(stream))
        {
            result = reader.ReadToEnd();
        }

        return result;