get an error in example "Push data into a Power BI dataset"

Hi,

I'm trying to figure out how push data into datasets through PowerBI API. Because of it I tried to execute example Push data into a Power BI dataset and at Step 5: Add rows to a Power BI table I got an error on this line:

var response = (HttpWebResponse)request.GetResponse();

Text of error:

Unhandled Exception: System.Net.WebException: The remote server returned an error: (404) Not Found.
at System.Net.HttpWebRequest.GetResponse()
at PushDataApp.Program.AddRows(String datasetId, String tableName) in c:\users\oleg\documents\visual studio 2017\Projects\PushDataApp\PushDataApp\Program.cs:line 174
at PushDataApp.Program.Main(String[] args) in c:\users\oleg\documents\visual studio 2017\Projects\PushDataApp\PushDataApp\Program.cs:line 31

Why is this happening?

And one more thing. In this example at Step 2: Get an authentication access token on next line:

string token = authContext.AcquireToken(resourceUri, clientID, new Uri(redirectUri)).AccessToken;

opens window where you need to enter email and password. Is there any way not to show this window and enter email/password in or through the program? I mean I (and users of my future program too) don't want to enter this data manually.

I'll appreciate any help.