atcom cannot connect to Telit modem

[mtbsteve]

I installed atcom as described, however I cannot connect to the Telit modem. Any AT commands result in the same error.

pi@raspberrypilte:~ $ atcom --port /dev/ttyUSB2 -b 115200 AT
[ERR]   Couldn't open serial communication
pi@raspberrypilte:~ $ 

If I run the connection via minicom minicom -D /dev/ttyUSB2 -b 115200 , everything works.

RasperryPI Bullseye, Python 3.9.2 installed.

EDIT: It found a connection at /dev/ttyUSB3. I accidentially tried USB2 since this is the right port address when I use minicom. However, the the automatic port scan seems not to work as I always need to add the -p option.