The wireless link could be bad, could be a firewall, could be a failed wireless HDMI system.
Samsung is notorious for updates that break such a thing so you try again wired and see if that works.
from one day to another a cant use my tv anymore as a second screen.
my laptop is a ACER ASPIRE E5-575G-79TG
my tv is a SAMSUNG UE40KU6400
can someone help me?