Make sure your laptop and your Tv are connected to the same network.
If you are using Windows 10 on your laptop Go to settings>Devices> Add device>WirelessDisplay and connect to your Tv.
Thank you again for your reply. I have to mention that i have this problem specifically With Hp Laptops . With other laptops and even with android smatphone i can be connected to my TV without problem.
Do you think that updating my TV could solve the problem? If so, could you please share with me a link to download the last update for my Samsung QE82N TV?