car push start button not flashing

Hi everyone, first time here.
I have a car alarm/push start button system installed from
Dowontec ST800.

Now normally once I get into the car (fob in my pocket), I simply depress the brake pedal and the start button will blink or flash. That indicates that it's ready and once I press it, the engine will start.

Everyone once in awhile, I'd depress the brake, but the push button would not blink. It would just stay lit on. In these cases, when I press the button, the engine doesn't start but only the power to the car is turned on (windows, radio, gps, etc.).
If I turn the power off and try again, same thing, the push button doesn't blink but only the ACC/power turns on for the car. Also, the brake pedal starts to feel stiffer and stiffer until it won't depress anymore.

So I'd have to start my car another way by holding down a button on my fob for 3 seconds.    

The past 3 days or so, it now ALWAYS does this. Before it was just once every 4 or 5 starts, but now it's been every single time I get in the car, and depress the brake pedal, the start button won't flash so I know I can't start the car's engine.

Now after turning it using the alternate method (pushing a button on my fob for 3 seconds), when I get to my destination and then turn off the car, if I depress the brake pedal, the push button blinks/flashes again as if it's working fine.

So I'm not sure what might be causing this? Could it be battery issue with the fob? Could it be a brake pedal switch issue? Or could it be my cellphone being too close to the fob (they are in the same pocket).

Thanks for any help!

Oh and my car is a 2011 Chevrolet Spark (overseas now, here it's called a Daewoo Matiz Creative), automatic, 1.0L engine.

Do the brake lights work? If so then you need to check the wiring where the remote start connects into the brake light circuit. If the brake lights don't work then you need to troubleshoot why they don't work (switch, fuse, plug, etc, etc).

PSA Rant: Please check your lights and ensure they work. Do this on some kind of regular basis. Bulbs don't last forever, they do burn out and need replacement.

Also for those with newer cars, please manually turn on your headlights at night or otherwise make sure all your lights are on when driving at night. With modern cars, daytime running lights (headlight illumination) and a lit up dash does NOT mean your lights are on. If you have a dark colored vehicle on a dark road and this is the case you might as well be invisible for everyone coming from behind and you're at a serious risk for an accident.

End Rant