I'm trying to connect to StackExchange API using OAuth. So far i've been able to get a token and retrive data that does not require authentication. When i try do query that uses the authentication, i'm getting error 400 - Bad request. Heres the code: Dim Key As String = "(app_key)" Dim RequestURL As String = "https://api.stackexchange.com/2.2/me/questions?access_token=" & Token & "key=" & Key & "&order=desc&sort=activity&site=stackapps" Dim Handler As HttpClientHandler = New HttpClientHandler() If Handler.SupportsAutomaticDecompression Then Handler.AutomaticDecompression = DecompressionMethods.GZip Or DecompressionMethods.Deflate End If Dim HttpClient As HttpClient = New HttpClient(Handler) Dim query = Await HttpClient.GetAsync(RequestURL) If query.IsSuccessStatusCode = True Then '(query.Content.ReadAsStringAsync()) End If Tried using only key, only access token, or none in the request, but received the same error. Also tried adding "OAuth" header and "access_token": HttpClient.DefaultRequestHeaders.Authorization = New AuthenticationHeaderValue("OAuth", Token) HttpClient.DefaultRequestHeaders.Authorization = New AuthenticationHeaderValue("access_token", Token) Any help appreciated.