EM7455: CID allocation failed in the CTL client

I’m trying to test Sierra Wireless EM7455 modem. I have the kernel configured and the module itself is detectable by the PC (Ubuntu 16.04) because I can see cdc-wdm0 and ttyUSB{0,1,2,3} in /dev directory. Furthermore when testing AT commands on ttyUSB2 I’m getting appropriate responses.

But, when trying to run command such as:

sudo qmicli -d /dev/cdc-wdm0 -p --nas-get-signal-strength

I’m getting:

error: couldn't create client for the 'nas' service: CID allocation failed in the CTL client: Transaction timed out

What is this indicative of ? what is the real issue here and how can I solve it ?

Thanks in advance for your advises.

It means that libqmi could not get a channel allocated by the modem to send the command to get signal strength. Please try libqmi forums if there is more information on the topic.