I Have interfaced arduino uno with sim800l module.I have used example programs define in sim800l library.The module blinks while starting and then blinks at a rate of 3binks per second after a time period.A voltage supply of 4.2 volt is given using a zener diode.The problem seems to be with the program(actually i am not sure whether it is a hardware or software issue).Some please give me neccessary guidance.