Two things are possible here. Firstly your remote battery maybe running low. To check this, press and hold the button down, the led must remain solid. If the LED flashes, your battery is low. Replace the battery.
If all remotes are reacting the same way, you will have to delete all the remotes in your receiver, when relearning each remote into the receiver, stand 20 meters or more away. This strengthens you receivers reception. All remotes should work at least 40 meters away.