Hi Komal,
Apologies for the long delay. I believe I’ve modified the slice so that they are both on a FabNetV4 connection, but they do not receive any ARP replies from the gateway so the pings still fail.
I am similarly experiencing this issue. I created a fresh bastion key, ran configure_and_validate which confirmed the key was valid, and my verbose printout is similar to the above. Within Jupyter this is causing slice creation post_boot configuration to fail due to authentication errors.