Snapcraft - Failed to install GPG Key

Hello Community,

I am trying to generate a snap from this source https://git.giaever.org/joachimmg/home-assistant-snap/src/master/snap/snapcraft.yaml 

As a first step, it tries to install deadsnakes-ppa package repository. But, it always encounters an issue of failed to install GPG key.

I am using Ctrlx Works V1.20.0 App development environment. 

I have tried the same on Ubuntu 20.04 based Virutal Machine on Virtual Box. It works fine there. I suspect the error in Ctrlx Works V1.20.0 App development environment is because of proxy.

I have tried to set proxy for snap through these commands.

sudo snap set system proxy.http="http://10.0.2.2:3128"

sudo snap set system proxy.https="http://10.0.2.2:3128"

But, still the error persists. Have anyone encountered such issues before? Please, let me know how to fix this.

Thanks & Regards