Failure in creating device certificate & provisioning it

I am creating device certificate as per steps mentioned at 

https://nordicsemiconductor.github.io/asset-tracker-cloud-docs/saga/docs/azure/GettingStarted/DeviceCredentials.html

Create root & intermediate certificates works fine, 

But when we issue 

node cli create-and-provision-device-cert

to create device certificate & provision it, it results in failure as follows:

node cli create-and-provision-device-cert --dk --debug --delete-private-key
Flasing certificate /dev/ttyACM0
Connecting to /dev/ttyACM0
Inactivity timeout 10 seconds
ERROR create-and-provision-device-cert failed!
ERROR Readline is not a constructor

Using Ubunto 20.x lts, using asset tracker 1.9x , firmware is created fine, it also works if I generate certificate using microsoft method for testing. 

@oys Let me know if you need more information