Why virt-p2v is failing with error "Conversion failed: NBD server error: timed out waiting for NBD server to start"

Issue

• virt-p2v fails immediately with the error Conversion failed: NBD server error: timed out waiting for NBD server to start.
• The logs in the physical machine where the p2v ISO is booted shows below error message.

Dec 13 13:19:58 localhost launch-virt-p2v[1278]: starting qemu-nbd for /dev/sda on localhost:50123
Dec 13 13:19:58 localhost launch-virt-p2v[1278]: qemu-nbd: Failed to bdrv_open '/dev/sda': Could not open '/dev/sda': No medium found: No medium found