Cannot login into lottosite URL by using https-URL and the get-method

[cdavinci]

I am programming a tool which shall automatically login into some freeotto-sites and automatically play predefined lotto-numbers. At the moment i programm the part for login into a lotto site URL. I found out the URL for logging in via URL. I just attach "username=xyz&password=zxy" and build a qnetworkrequest with the full necessary URL. By using the get-method of the qnetworkaccesmanager i try to login. The reply-signal "finished is catched by my slot-method without an error , but the returned content is empty ! When i try exactly the same URL in the firefox-browser loging in works !

What shall do to login with my QT-code ?