Autonomo sleeping without serial

Hi all,
I’m a software-guy doing some hardware now, however I have some difficulties with the Autonomo. I have an Autonomo which has a great LoRa (KPN) connection at the moment. However, after unplugging the device from my laptop (running arduino software) and plugging it in with a separate power supply, the thing just freezes. There is no output seen on the wlogger from KPN. I used anything between 4,7 and 5,3 v, but I don’t think this is the problem. I think it has something to do with the serial monitor or something in this direction, however I’m to inexperienced with the whole hardware thing to debug it.
Anyone?

Do have any code which waits for the SerialUSB connection?

while (!SerialUSB);

This will block until a connection to the virtual COM port is opened via USB.

I’m very sorry. I must have scrolled over it dozens of time. After a system crash I recovered my arduino-code from a different file and completely missed it. I did a search on your suggestion and saw it almost instantly. My bad!!
I will have physical access tomorrow and I’m sure this will solve the issue.