Check circuit breaker.
Click fully off and then back on.
Check for burned smell at breaker or loose crackling sound that says breaker is bad.
Reset timer. Then Reprogram.
Possible geyser timer manual
http://waterheatertimer.org/pdf/Digital-Geyser-Timer 24H-7-Day-Timer-230V Brochure.pdf
This timer has a non-replaceable internal rechargeable battery.
If battery has gone bad, then timer is defunct.
Use manual override button to turn timer ON-OFF.
Then test across terminals 3 and 4 for 240Volts.
Turn timer OFF, and test across terminals 4 and 5 for 240Volts
If no voltage shows then timer does not have output.
If test shows 80% undervoltage, that can cause load not to activate, depending on type of load.
Have electrician check for voltage issues at power company transformer.
Unknown what load timer is connected to.
Max load for this timer at 240 volts is 3680 watts, 16 amps.
Motor load is 230 volt 8 amps.
Check label on load for watt or amp rating.
Volts x amps = watts
Watts divided by volts = amps
If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7