I am quite new to linux. I have two BeagleBone Black PCs with Yantrr Vayu2 4G modem, running on Debian 10. I am connecting to the internet using the ppp protocol and rnet. On first PC everything works fine. On the other one after while all /dev/ttyUSBXX are missing. The modem is connected via USB cable but I think it is not recognized. I tried everything but nothing works. I appriciate any help. Thank you!