Hi Just add HardwareSerial Serial2(2); under #include <Arduino.h> in /Users/matthias/Documents/Arduino/libraries/M5Stack/src/LoRaWan.h

So, I have 2 m5stack core with me. My idea is to have these 2(or potentially more) to communicate with each other via LoRa, one to be a sensor node, and another acts as a receiver. The receiving node will then upload the data received from the sensing node to thingspeak. The components used in this system is the ENV sensor, and the LoRa modules. I hope this explains what I am trying to do.

most M5Stack Arduino API , you can find it from this page. link:https://docs.m5stack.com/#/en/arduino/arduino_api