The power cord isn't fully seated or the unit isn't plugged into a working outlet.
Check the power cord connection at the back of the unit. Plug it firmly into a 120V AC electrical outlet. Test the outlet with another device. Press the Power button again.
If that didn't work, the appliance may have tripped its internal thermal safety. Unplug it for 60 minutes to let it cool completely. Plug it back in and try again.
Heads up: Never use an extension cord. The high wattage can overload it. If it still doesn't power on after these steps, contact Cuisinart Customer Service.