Review the timer instructions located on the inside door of the control box. If the timer screen is blank then check to see if it is receiving power. Check to make sure it is plugged in and verify the outlet has power.
If the outlet has no power a GFCI outlet or
breaker in the electrical panel may have tripped. Be aware a GFCI outlet can be located in a variety of locations, for example bathroom, kitchen or garage. If the date and time displayed on the timer are correct then it may be a component issue, contact customer service.