WebRequest delay on receiving data

 

Hello everyone, I have a question about the WebRequest function.
I have a software who updates correctly on my website a file (every 10 seconds) through FTP.
The problem is when I use WebRequest to get the last new data...

The first time I do the request it shows me the new last data correctly, but when I do a second time and so on (after 1 or 2 minutes), it continues to show me the first data (when I called the first time), and it only updates the request after two hours or so.
It's very strange. Have you ever had this problem? Can you help me please?
Here below a picture where you can see better the problem

WebRequest delay problem