What is the model of your TV?
If you have the tv connected to a power bar try connecting the tv directly to the power outlet or try to connect the tv to a different outlet.
Also try press and holding the power button on the tv 5 to 10 seconds, usually the power button is on the bottom right side of the screen very close to the stand-by light...
My Samsung smart tv that I haven't even had for 2 years has suddenly started turning itself off and on. Not only this, but it also does not pick up any signals from my remote. I am unable to change anything and am not sure if there is a fix for the off/on problem without the remote.