I can't get my TV to play sound when I use my

So the cable worked fine when I got it. Then the sound was only coming through my computer. So I googled it, and all I had to do was set the HDMI as my default sound and make sure it was enabled. That worked, for a little bit. Now have the same problem. It says the HDMI is enabled, but now it says it isn't connected! And I know that it is connected!!! PLEASE HELP!