If HDMI fails to "handshake" the port may not work until the devices are powered down and get a fresh start. There can be issues with older HDMI cords so only the newer tech would fail to pack a shiny new 1.4 or later spec cord with them. AmazonBasics are under 9 bucks so said tech does not have a reason to not carry it with them.
So, power it all off, disconnect it all, remove the AC power cord, go have some coffee/tea/water and then try again but DO NOT plug in anything but what you want to work.
New Samsung HD TV...new Samsung Blu Ray. TV does not recognize Blu Ray....no idea what to do...have checked all cords......old DVD player works with TV. Not tech smart.