Ok, I think the project using the Pro Micro ends here. I did some testing (with NRF024 radio module) and I got it working. But the switching of USB ports (bootloader/serial port) is to much hassle. Very tricky to read the serial debug data because after each reset the serial port is unloaded and loads again, giving my serial program a "port not found ", the classis chicken-egg situation. I will switch over to the RFM69 radio module, but no Pro Micro.

Hi @Rolo6442u - welcome! st=fail means the radiotraffic between the node and gateway fails in some way. Sometimes it can reach the gw, but some more skilled in the code need to present you with the details. If you use a nrf radio and you dont use a 4.7uF cap on VCC-GND thats a good advice.