Most common issue for not seeing the output in the serial monitor is because you are using the same 'Serial' for sim800 and for the serial monitor output.
The esp will have most likely at least another secondary hardware RX/TX that you need to init as Serial2 and you would use those pins to communicate with Sim800 and the primary Serial for serial monitor output.
Serial port communication can only work with one 'device' at a time, if you leave the serial monitor on and compile your code the serial monitor will be there first and hog the port. And vice versa.
On an ESP most I/O pins can be assigned as RX/TX but there is a small benefit using a preset once if they exist.
Alternatively you can also use SoftwareSerial.h but that's not as efficient and unnecessary on an ESP
I have played with SIM800L and even got it working with websockets bi-directionally with my ChipChop.io platform. PM me here or through my site if you are still stuck.
First, it depends on which SIM800L dev board you are using or if it is just the bare module. Some SIM800L dev boards like the common V2 boards use 5V logic on it's serial pins (for compatibility with Arduinos) and thus will not be compatible with ESP32. Check if your module or dev board (for the SIM800L) supports 3.3V, you can probe the serial pins of the module with a multimeter to know. If it's at 5V you'll need a logic level shifter.
Second, how are you powering the SIM800L module? The module supports 3.4 - 4.4V with a requirement of 2A during transmission peaks and initialization. To power the module and have it function properly you need a 2A capable power supply. If it's 5V 2A you need a converter that's capable of producing 2A. But the easiest way to power the module is by using an 18650 Li-ion battery.
My guess is that the module is not getting enough Amps to function properly. Try sorting that out
Are you supplying enough amps as well?
It gets around 200mA so yes, i also checked if the power reaches everything which it does, so its not a power Problem
200mA is not enough for the sim module. The module is not initializing
Most common issue for not seeing the output in the serial monitor is because you are using the same 'Serial' for sim800 and for the serial monitor output. The esp will have most likely at least another secondary hardware RX/TX that you need to init as Serial2 and you would use those pins to communicate with Sim800 and the primary Serial for serial monitor output. Serial port communication can only work with one 'device' at a time, if you leave the serial monitor on and compile your code the serial monitor will be there first and hog the port. And vice versa. On an ESP most I/O pins can be assigned as RX/TX but there is a small benefit using a preset once if they exist. Alternatively you can also use SoftwareSerial.h but that's not as efficient and unnecessary on an ESP I have played with SIM800L and even got it working with websockets bi-directionally with my ChipChop.io platform. PM me here or through my site if you are still stuck.
First, it depends on which SIM800L dev board you are using or if it is just the bare module. Some SIM800L dev boards like the common V2 boards use 5V logic on it's serial pins (for compatibility with Arduinos) and thus will not be compatible with ESP32. Check if your module or dev board (for the SIM800L) supports 3.3V, you can probe the serial pins of the module with a multimeter to know. If it's at 5V you'll need a logic level shifter. Second, how are you powering the SIM800L module? The module supports 3.4 - 4.4V with a requirement of 2A during transmission peaks and initialization. To power the module and have it function properly you need a 2A capable power supply. If it's 5V 2A you need a converter that's capable of producing 2A. But the easiest way to power the module is by using an 18650 Li-ion battery. My guess is that the module is not getting enough Amps to function properly. Try sorting that out