SIM800L really works?

  • Hi, I have a module SIM800L for the M5stack. Does anyone use the SIM800L module? Sometimes it works, sometimes not. If I send a simple command like AT or something similar, no problem. But if I use an HTTP request or an other complex operation, sometimes it works and sometimes not. I obtain different errors from the module, but usually the errors are generic and not useful to understand where is the problem. If I use the same source code in a different module, for example a SIM808 or with an external SIM800L the code works well, when I use the SIM800L module with the M5stack I have the problems. Do you have some example of usage in a real environment, not sending simple SMS but something with GET or POST requests? I use a 5V 3A power supply (the official Raspberry PI 4 power supply) so I think I have enough current for the module. But I used also a 5V 2.4A mobile power supply with the same problems.
    I now ordered a new SIM800L module, maybe my module doesn't work well. I don't know what to think. Any suggestions or tips?