My Vizio tv a lil direct tv box have always worked with HDMI cables now it's saying that my tv does not support this what do I do

Can anyone help me 

Check to see if the TV has the latest software.

Mine is saying same thing

What is the exact on-screen message?

What DVR/Receiver model number do you have?

Have you tried resetting the DVR/Receiver?

Have you tried reseating the HDMI cable?

It's stuck in 480 resolution it used to be in 1080 now I can't watch anything 

It want let me switch to a higher format 

Please answer my previous questions.