Qmi stalled MC7455



I am trying to set up qmi for 4G connection. I have installed all the required libraries like: usb-modeswitch kmod-mii kmod-usb-net kmod-usb-wdm kmod-usb-net-qmi-wwan uqmi. Then I used LUCI to configure QMI cellular, these are my 4G config in network:

config interface ‘4G’
option proto ‘qmi’
option apn ‘myapn’
option device ‘/dev/cdc-wdm0’
Then I used putty to ssh into my router, I and entered the commands like:
ifup 4G : this command skipped then goto next command.
uqmi -d /dev/cdc-wdm0 --get-data-status : this command just stalled until ctl-C
and any other commands that start with uqmi just stalled until ctl-C.

I think my qmi protocol hasnt been properly configured and activated.

I am using Sierra MC7455 with ZBT we826.

Can anyone please give me a hint to get through this problem.

Thank you in advance.