Why I cannot access Yobit API using webclient - webclient

Question

The code used to work.
The URL in question is
https://yobit.net/api/3/info
It works in IE. It used to work with webclient. It doesn't work in webclient now. And I wonder what the problem is
Suddenly it stops working. So I am checking
Try
Dim wc = New WebClient
wc.Headers.Add("Accept", "text/html, application/xhtml+xml, image/jxr, */*")
wc.Headers.Add("Accept-Encoding", "gzip, deflate")
wc.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko")
wc.Headers.Add("Accept-Language", "en-US,en;q=0.5")
wc.DownloadString(URL)
Catch ex As Exception
End Try
I also tried simple version. Not working
Try
Dim wc = New WebClient
wc.DownloadString(URL)
Catch ex As Exception
End Try
In both cases yobit throw 503 access denied exception
I use fiddler and try to use internetexplorer to access directly
It works fine
GET https://yobit.net/api/3/info HTTP/1.1
Accept: text/html, application/xhtml+xml, image/jxr, */*
Accept-Language: en-US,en;q=0.5
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
Accept-Encoding: gzip, deflate
Host: yobit.net
Connection: Keep-Alive
Cookie: __cfduid=de63c60d603f271520b9ee58dfdd257061517932785; cf_clearance=7e58588df28b267842f753567dcdc475d29679a6-1517932789-86400; locale=en
If I use webclient this is the header
GET https://yobit.net/api/3/info HTTP/1.1
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.5
Accept: text/html, application/xhtml+xml, image/jxr, */*
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
Host: yobit.net
Connection: Keep-Alive
Almost the exact same thing.
Let me try another URL
Say http://google.com
GET http://www.google.com/ HTTP/1.1
Accept: text/html, application/xhtml+xml, image/jxr, */*
Accept-Language: en-US,en;q=0.5
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
Accept-Encoding: gzip, deflate
Host: www.google.com
Connection: Keep-Alive
Cookie: NID=121=GUd4VKHT_gcwUx-hK39mphuCg93Q_W2fL_yCc-JO3AJkgh74EGajif0537eraLK8ns2EdEQPexOOeBxSlOxVrj8t_AVn21FRme2hAxuLXz4F8aCZExIzME4jaYMBuUp_lnak5Q; OGPC=19004116-3:; 1P_JAR=2018-1-9-7
If I use webclient
GET http://google.com/ HTTP/1.1
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.5
Accept: text/html, application/xhtml+xml, image/jxr, */*
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
Host: google.com
Connection: Keep-Alive
Both works.

Answer 1

There could be different issues here
Framework Version
You recently changed the framework version and that has some issue which causes it not to work. You can change the framework versions and see if it helps
Compression of Data
WebClient by default is not doing decompression and you add headers to request gzip data if available. Now there is a possibility that the site didn't enable gzip earlier which made it work for you and now they have enabled gzip responses. You can fix that by changing
wc.Headers.Add("Accept-Encoding", "gzip, deflate")
to
wc.Headers.Add("Accept-Encoding", "deflate")
Or if you want the data to come in compressed form only, then you can enable auto decompression as shown in below code
class Program
{
class MyWebClient : WebClient
{
protected override WebRequest GetWebRequest(Uri address)
{
var request = base.GetWebRequest(address) as HttpWebRequest;
request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
return request;
}
}
public static void Main(string[] args)
{
var URL = "https://yobit.net/api/3/info";
var wc = new WebClient();
wc.Headers.Add("Accept", "text/html, application/xhtml+xml, image/jxr, */*");
wc.Headers.Add("Accept-Encoding", "gzip, deflate");
wc.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko");
wc.Headers.Add("Accept-Language", "en-US,en;q=0.5");
Console.WriteLine(wc.DownloadString(URL));
// TODO: Implement Functionality Here
Console.Write("Press any key to continue . . . ");
Console.ReadKey(true);
}
}
The above example is C# and not VB.NET but you can easily convert it