If your coffee maker isn't starting, there are a few potential reasons why. The most common reason is that the coffee maker isn't plugged in. Make sure that the coffee maker is plugged into an outlet and that the power switch is turned on. If it's still not working, check to see if there's a tripped circuit breaker or blown fuse.
Another possibility is that the water reservoir is empty. The coffee maker won't start if there's no water in the reservoir. So, make sure to add water to the reservoir before trying to start the coffee maker again.
Finally, some coffee makers have an automatic shut-off feature that kicks in after a certain amount of time. This could be why your coffee maker isn't starting. To fix this, simply unplug the coffee maker for 30 seconds and then plug it back in again. This should reset the shut-off timer and allow you to use your coffee maker again as normal.