EVE Technology Lab

I've gotten to the point where I've got an access token but whenever I make the request to get the endpoint list I get 400 Bad Request error. I've tried several variations of the header but can't seem to put my finger on my mistake. If any of you experts out there have a moment would you take look at this snippet and let me know if you see the problem?

HttpWebRequest request = WebRequest.CreateHttp( "https://crest-tq.eveonline.com/" );
request.Proxy = null;
//request.ContentType = "application/x-www-form-urlencoded";
request.Method = "POST";
request.Headers.Add( "Authorization", "Bearer " + _accessToken );
//request.Accept = "application/vnd.ccp.eve.Api-v3+json; charset=utf-8";
request.Host = "crest-tq.eveonline.com";
request.ContentLength = 0;

var response = request.GetResponse();

Another thing that I'm not clear on; when I verify the auth code I get an access token but not a refresh token. Furthermore it seems the access token expires after a few minutes, forcing me to start over. This doesn't seem to be working as intended so I figure I must be not catching on to something. Can anyone offer any guidance on this?

Thanks for any help :)