Sim800l not connecting to network

I wanted to use the sim800l to send data from sensors, however the connection is unstable. Sometimes it does connect, others not. Is it normal on this module? I have measure the voltage and it does not drop from 3.4V, I am also using resistors to drop down the voltage to the RX pin, and I have used the chip on my phone and it works fine. What can be wrong?

I don't know which country you are at.
2G is almost completely phased out in the USA.


A bit more detail maybe needed, we cannot see your project.......