Why "QMI protocol error (14)"

[jyijyi]

Can you try with another sim card without authentication requirement?
BTW, did you also try AT+CGAUTH?

You can also try AT!SCACT to see if it can establish data connection:

Example on establishing data connection by AT!SCACT via MBPL R20 driver

Here is an example to establish data connection by AT!SCACT via MBPL R20 driver: Module: WP7609 FW: R13 MBPL: R20 PC Environment: Ubuntu 18 need to install the MBPL R20 driver for qmi_wwan and qcserial (MBPL_Drivers_USB_R20_ENG1-src.tar.gz) avoid the Ubuntu changing the network name: ln -s /dev/null /etc/systemd/network/99-default.link sudo apt-get install libqmi-utils sudo apt-get install udhcpc now insert the USB to PC sudo chmod 777 /sys/class/net/wwan0/qmi/raw_ip …