Remove everything from the outlet of the hose faucet timer
Turn the water on and cover the outlet of the timer with your thumb
Hold your thumb in place and then turn on the timer manually
Once you hear/feel a click, remove your thumb
The water should begin spraying out of the outlet, so you may get wet from this
If water is still not flowing, take the HoseTimer off of the spigot and check for any debris on the inlet
Take the screen out of the inlet and check out any debris and place the screen back inside the inlet
Reattach to hose spigot and manually turn the HoseTimer on to let water flow through
Try removing batteries and reinserting them, confirming the batteries aren’t too old, and then resetting the timer.